Dialyzer Reuse and Outcomes of High Flux Dialysis.

PubMed

Argyropoulos, Christos; Roumelioti, Maria-Eleni; Sattar, Abdus; Kellum, John A; Weissfeld, Lisa; Unruh, Mark L

2015-01-01

The bulk of randomized trial evidence for the expanding use of High Flux (HF) hemodialysis worldwide comes from two randomized controlled trials, one of which (HEMODIALYSIS, HEMO) allowed, while the other (Membrane Outcomes Permeability, MPO) excluded, the reuse of membranes. It is not known whether dialyzer reuse has a differential impact on outcomes with HF vs low flyx (LF) dialyzers. Proportional Hazards Models and Joint Models for longitudinal measures and survival outcomes were used in HEMO to analyze the relationship between β2-microglobulin (β2M) concentration, flux, and reuse. Meta-analysis and regression techniques were used to synthesize the evidence for HF dialysis from HEMO and MPO. In HEMO, minimally reused (< 6 times) HF dialyzers were associated with a hazard ratio (HR) of 0.67 (95% confidence interval, 95%CI: 0.48-0.92, p = 0.015), 0.64 (95%CI: 0.44 - 0.95, p = 0.03), 0.61 (95%CI: 0.41 - 0.90, p = 0.012), 0.53 (95%CI: 0.28 - 1.02, p = 0.057) relative to minimally reused LF ones for all cause, cardiovascular, cardiac and infectious mortality respectively. These relationships reversed for extensively reused membranes (p for interaction between reuse and flux < 0.001, p = 0.005) for death from all cause and cardiovascular causes, while similar trends were noted for cardiac and infectious mortality (p of interaction between reuse and flux of 0.10 and 0.08 respectively). Reduction of β2M explained only 1/3 of the effect of minimally reused HF dialyzers on all cause mortality, while non-β2M related factors explained the apparent attenuation of the benefit with more extensively reused dialyzers. Meta-regression of HEMO and MPO estimated an adjusted HR of 0.63 (95% CI: 0.51-0.78) for non-reused HF dialyzers compared with non-reused LF membranes. This secondary analysis and synthesis of two large hemodialysis trials supports the widespread use of HF dialyzers in clinical hemodialysis over the last decade. A mechanistic understanding of the effects of HF dialysis and the reuse process on dialyzers may suggest novel biomarkers for uremic toxicity and may accelerate membrane technology innovations that will improve patient outcomes.

Transfer factor - hypotheses for its structure and function.

PubMed

Shifrine, M; Scibienski, R

1975-01-01

Transfer factor (TF) is a dialyzable extract from primed lymphocytes that is able to transfer specific delayed hypersensitivity from one animal to another. On the basis of available data we suggest that TF is a polypeptide with a molecular weight below 15,000 daltons. We hypothesize that TF is the variable light or heavy chain domain of immunoglobulin: such a molecule conforms with the accepted properties of TF and also has the necessary specificity requirements. We also hypothesize that TF is part of a receptor site. beta-2-microglobulin, a molecule that is an integral part of cell surfaces, could be the anchor for TF. beta-2-microglobulin has homologies with the constant portion of immunoglobulin light or heavy chain and thus would combine with the variable domain (TF) to form a complete receptor site for a specific antigen. The properties of TF suggest its mode of action, which is discussed in detail in the text. The biologic advantages of TF is its ability to confer immediate (immunologie specific) protection while the 'normal' immune response develops.

A new synthetic dialyzer with advanced permselectivity for enhanced low-molecular weight protein removal.

PubMed

Krieter, Detlef H; Lemke, Horst-Dieter; Wanner, Christoph

2008-07-01

Optimizing solute removal at minimized albumin loss is a major goal of dialyzer engineering. In a prospective, randomized, crossover study on eight patients (age 63 +/- 14 years) on maintenance hemodialysis, the new Baxter Xenium 170 high-flux dialyzer (BX), which contains a 1.7-m(2) PUREMA H dialysis membrane, was compared with two widely used reference high-flux dialyzers currently available for hemodialysis in North America, the Fresenius Optiflux 180 NR (FO) and the Gambro Polyflux 170 H (GP). Solute removal and biocompatibility were assessed in hemodialysis for 240 min at blood and dialysate flow rates of 300 and 500 mL/min, respectively. Additional ex vivo experiments detecting the interleukin-1beta (IL-1b) generation in recirculated donor blood were performed to demonstrate the pyrogen retention properties of the dialyzers. The instantaneous plasma clearances were similar for the three dialyzers except for cystatin c (cysc), for which a lower clearance was measured with FO as compared with BX and GP after 30 and 180 min of hemodialysis. The reduction ratios (RRs) corrected for the hemoconcentration of beta(2)-microglobulin and cysc were lower in FO (44 +/- 9 and 35 +/- 9%, respectively) versus BX (62 +/- 6 and 59 +/- 7%, respectively) and GP (61 +/- 7 and 56 +/- 8%, respectively). The RRs of the cytokine tumor necrosis factor alpha and interleukin-6 were not different between the dialyzers. The albumin loss was <300 mg for all filters. No differences between the dialyzers were found in the biocompatibility parameters showing very low leukocyte and complement activation. The ex vivo recirculation experiments revealed a significantly higher IL-1b generation for GP (710 +/- 585 pg/mL) versus BX (317 +/- 211 pg/mL) and FO (151 +/- 38 pg/mL). BX is characterized by a steep solute sieving profile with high low-molecular weight protein removal at virtually no albumin loss and an excellent biocompatibility. This improved performance may be regarded as a contribution to optimal dialysis therapy.

Dialysate Flow Rate and Delivered Kt/Vurea for Dialyzers with Enhanced Dialysate Flow Distribution

PubMed Central

Idoux, John W.; Hamdan, Hiba; Ouseph, Rosemary; Depner, Thomas A.; Golper, Thomas A.

2011-01-01

Summary Background and objectives Previous in vitro and clinical studies showed that the urea mass transfer-area coefficient (KoA) increased with increasing dialysate flow rate. This observation led to increased dialysate flow rates in an attempt to maximize the delivered dose of dialysis (Kt/Vurea). Recently, we showed that urea KoA was independent of dialysate flow rate in the range 500 to 800 ml/min for dialyzers incorporating features to enhance dialysate flow distribution, suggesting that increasing the dialysate flow rate with such dialyzers would not significantly increase delivered Kt/Vurea. Design, setting, participants, & measurements We performed a multi-center randomized clinical trial to compare delivered Kt/Vurea at dialysate flow rates of 600 and 800 ml/min in 42 patients. All other aspects of the dialysis prescription, including treatment time, blood flow rate, and dialyzer, were kept constant for a given patient. Delivered single-pool and equilibrated Kt/Vurea were calculated from pre- and postdialysis plasma urea concentrations, and ionic Kt/V was determined from serial measurements of ionic dialysance made throughout each treatment. Results Delivered Kt/Vurea differed between centers; however, the difference in Kt/Vurea between dialysate flow rates of 800 and 600 ml/min was NS by any measure (95% confidence intervals of −0.064 to 0.024 for single-pool Kt/Vurea, −0.051 to 0.023 for equilibrated Kt/Vurea, and −0.029 to 0.099 for ionic Kt/V). Conclusions These data suggest that increasing the dialysate flow rate beyond 600 ml/min for these dialyzers offers no benefit in terms of delivered Kt/Vurea. PMID:21799145

Epidermodysplasia verruciformis: response to therapy with dialyzable leukocyte extract (transfer factor) derived from household contacts.

PubMed

Vasily, D B; Miller, O F; Fudenberg, H H; Goust, J M; Wilson, G B

1984-05-01

Dialyzable leukocyte extracts (DLE) have been used to treat a variety of antigen selective, and broad spectrum immunodeficiency diseases with sometimes encouraging results. We describe here the clinical and laboratory responses to DLE therapy of 2 patients with epidermodysplasia verruciformis (EV), a chronic cutaneous infection with a variety of human papilloma viruses. One patient with longstanding (30 yr) disease and no improvement to previous therapy showed gradual yet definite resolution of extensive verrucae planae, plaque, tinea-versicolor-like, and tumor lesions scattered over his entire integument. Cessation of DLE therapy for a short time resulted in recurrence of partially regressed lesions and also in the development of new tumors in this patient. The second patient, a grandson of the first patient, with minimal disease showed no progression of the disease during DLE prophylaxis. A third subject (brother of patient number 2) received no DLE and served as a control. All 3 subjects demonstrated severely depressed levels of suppressor T cells, a defect in cell-mediated immunity that has not been hitherto reported in patients with EV. Finally, evidence is presented for a possible X-linked recessive mode of inheritance for susceptibility to EV.

Comparison of the effects of polysulfone and polyester-polymer alloy dialyzers on glycemic control in diabetic patients undergoing hemodialysis.

PubMed

Abe, M; Okada, K; Maruyama, T; Ikeda, K; Kikuchi, F; Kaizu, K; Matsumoto, K

2009-05-01

Though different high-flux dialyzers are available, there are no comparative studies on their glycemic control effects on diabetic hemodialysis (HD) patients. In this crossover study, we compared the effects of polysulfone (PS) and polyester-polymer alloy (PEPA) dialyzers. We recruited 47 diabetic HD patients. The conventional dialyzers were replaced with PS or PEPA dialyzers and the patients were treated for 16 weeks. Subsequently, after interchanging the PS and PEPA dialyzers, the treatment continued for another 16 weeks. For each dialyzer, we analyzed the glycemic control effect and measured their clearance and reduction rates of insulin. The PEPA dialyzer lowered the glycated albumin (GA) levels more significantly than the PS dialyzer. While the groups exhibited no differences in metabolic parameters, the clearance and reduction rates of insulin were more significant in the PS. A significant decrease was observed in the levels of GA, fasting plasma glucose, and glycated hemoglobin in patients with lower fasting C-peptide levels (< 6.0 ng/ml). Glycemic control in diabetic HD patients is affected by the type of dialyzer used. Our results indicate that the PEPA dialyzer is more potent in controlling glycemia than the PS dialyzer in diabetic HD patients.

Effect of dialyzer membrane materials on survival in chronic hemodialysis patients: Results from the annual survey of the Japanese Nationwide Dialysis Registry

PubMed Central

Hamano, Takayuki; Wada, Atsushi; Nakai, Shigeru; Masakane, Ikuto

2017-01-01

Background Little information is available regarding which type of dialyzer membrane results in good prognosis in patients on chronic hemodialysis. Therefore, we conducted a cohort study from a nationwide registry of hemodialysis patients in Japan to establish the association between different dialyzer membranes and mortality rates. Methods We followed 142,412 patients on maintenance hemodialysis (female, 39.1%; mean age, 64.8 ± 12.3 years; median dialysis duration, 7 [4–12] years) for a year from 2008 to 2009. We included patients treated with seven types of high-flux dialyzer membranes at baseline, including cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester polymer alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause mortality as hazard ratios (HRs) and 95% confidence intervals for 1-year mortality adjusting for potential confounders, and propensity score matching analysis was performed. Results The distribution of patients treated with each membrane was as follows: PS (56.0%), CTA (17.3%), PES (12.0%), PEPA (7.5%), PMMA (4.9%), PAN (1.2%), and EVAL (1.1%). When data were adjusted using basic factors, with PS as a reference group, the mortality rate was significantly higher in all groups except for the PES group. When data were further adjusted for dialysis-related factors, HRs were significantly higher for the CTA, EVAL, and PEPA groups. When the data were further adjusted for nutrition-and inflammation-related factors, HRs were significantly lower for the PMMA and PES groups compared with the PS group. After propensity score matching, HRs were significantly lower for the PMMA group than for the PS group. Conclusion The results suggest that the use of different membrane types may affect mortality in hemodialysis patients. However, further long-term prospective studies are needed to clarify these findings, including whether the use of the PMMA membrane can improve prognosis. PMID:28910324

Effect of dialyzer membrane materials on survival in chronic hemodialysis patients: Results from the annual survey of the Japanese Nationwide Dialysis Registry.

PubMed

Abe, Masanori; Hamano, Takayuki; Wada, Atsushi; Nakai, Shigeru; Masakane, Ikuto

2017-01-01

Little information is available regarding which type of dialyzer membrane results in good prognosis in patients on chronic hemodialysis. Therefore, we conducted a cohort study from a nationwide registry of hemodialysis patients in Japan to establish the association between different dialyzer membranes and mortality rates. We followed 142,412 patients on maintenance hemodialysis (female, 39.1%; mean age, 64.8 ± 12.3 years; median dialysis duration, 7 [4-12] years) for a year from 2008 to 2009. We included patients treated with seven types of high-flux dialyzer membranes at baseline, including cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester polymer alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause mortality as hazard ratios (HRs) and 95% confidence intervals for 1-year mortality adjusting for potential confounders, and propensity score matching analysis was performed. The distribution of patients treated with each membrane was as follows: PS (56.0%), CTA (17.3%), PES (12.0%), PEPA (7.5%), PMMA (4.9%), PAN (1.2%), and EVAL (1.1%). When data were adjusted using basic factors, with PS as a reference group, the mortality rate was significantly higher in all groups except for the PES group. When data were further adjusted for dialysis-related factors, HRs were significantly higher for the CTA, EVAL, and PEPA groups. When the data were further adjusted for nutrition-and inflammation-related factors, HRs were significantly lower for the PMMA and PES groups compared with the PS group. After propensity score matching, HRs were significantly lower for the PMMA group than for the PS group. The results suggest that the use of different membrane types may affect mortality in hemodialysis patients. However, further long-term prospective studies are needed to clarify these findings, including whether the use of the PMMA membrane can improve prognosis.

Dialyzer Reuse and Outcomes of High Flux Dialysis

PubMed Central

Argyropoulos, Christos; Roumelioti, Maria-Eleni; Sattar, Abdus; Kellum, John A.; Weissfeld, Lisa; Unruh, Mark L.

2015-01-01

Background The bulk of randomized trial evidence for the expanding use of High Flux (HF) hemodialysis worldwide comes from two randomized controlled trials, one of which (HEMODIALYSIS, HEMO) allowed, while the other (Membrane Outcomes Permeability, MPO) excluded, the reuse of membranes. It is not known whether dialyzer reuse has a differential impact on outcomes with HF vs low flyx (LF) dialyzers. Methods Proportional Hazards Models and Joint Models for longitudinal measures and survival outcomes were used in HEMO to analyze the relationship between β2-microglobulin (β2M) concentration, flux, and reuse. Meta-analysis and regression techniques were used to synthesize the evidence for HF dialysis from HEMO and MPO. Findings In HEMO, minimally reused (< 6 times) HF dialyzers were associated with a hazard ratio (HR) of 0.67 (95% confidence interval, 95%CI: 0.48–0.92, p = 0.015), 0.64 (95%CI: 0.44 – 0.95, p = 0.03), 0.61 (95%CI: 0.41 – 0.90, p = 0.012), 0.53 (95%CI: 0.28 – 1.02, p = 0.057) relative to minimally reused LF ones for all cause, cardiovascular, cardiac and infectious mortality respectively. These relationships reversed for extensively reused membranes (p for interaction between reuse and flux < 0.001, p = 0.005) for death from all cause and cardiovascular causes, while similar trends were noted for cardiac and infectious mortality (p of interaction between reuse and flux of 0.10 and 0.08 respectively). Reduction of β2M explained only 1/3 of the effect of minimally reused HF dialyzers on all cause mortality, while non-β2M related factors explained the apparent attenuation of the benefit with more extensively reused dialyzers. Meta-regression of HEMO and MPO estimated an adjusted HR of 0.63 (95% CI: 0.51–0.78) for non-reused HF dialyzers compared with non-reused LF membranes. Conclusions This secondary analysis and synthesis of two large hemodialysis trials supports the widespread use of HF dialyzers in clinical hemodialysis over the last decade. A mechanistic understanding of the effects of HF dialysis and the reuse process on dialyzers may suggest novel biomarkers for uremic toxicity and may accelerate membrane technology innovations that will improve patient outcomes. PMID:26057383

Development of dialyzer with immobilized glycoconjugate polymers for removal of Shiga-toxin.

PubMed

Miyagawa, Atsushi; Watanabe, Miho; Igai, Katsura; Kasuya, Maria Carmelita Z; Natori, Yasuhiro; Nishikawa, Kiyotaka; Hatanaka, Kenichi

2006-06-01

The dialyzer for Shiga-toxin elimination was developed and its performance was established. The dialyzer was prepared by immobilization of multivalent ligands. Glycoconjugate polymers having oligosaccharides and amino groups were synthesized to function as Shiga-toxin adsorbents. The amino group was utilized to immobilize the polymer inside the cellulose hollow fiber of the dialyzer. Cellulose hollow fibers packed in the dialyzer were carboxymethylated under moderate conditions. The glycoconjugate polymers were bound covalently to the hollow fibers of the dialyzer by condensation reaction between the amino group of the polymer and the carboxyl group of the cellulose hollow fiber. Shiga-toxin eliminabilities of the prepared dialyzers were evaluated at various conditions. Even at high concentration of protein such as FCS, the dialyzer showed an excellent performance for Shiga-toxin adsorption.

The role of dialyzer membrane flux in bio-incompatibility.

PubMed

Davenport, Andrew

2008-10-01

Dialyzer membrane flux is currently defined according to beta(2)-microglobulin (a middle molecule) clearance. Traditionally, high flux membranes were synthetic, and caused less inflammatory reaction in the extracorporeal circuit, compared with standard low-flux cuprophan bio-incompatible dialyzers. Initial reports suggested improved patient outcomes in acute renal failure when noncuprophan dialyzer membranes were used. However, over time these positive observations have not been substantiated. As the price differential between these dialyzer membrane types has become marginal, more high-flux dialyzers are now used in routine clinical practice. Two multicenter trials have recently reported a survival advantage for high-flux dialyzers. Whether this is directly consequent upon the choice of dialyzer membrane, or related to improvements in dialysate water quality, or changes in other clinical practices remains to be determined.

Differences in bio-incompatibility among four biocompatible dialyzer membranes using in maintenance hemodialysis patients.

PubMed

Zhang, Dong-Liang; Liu, Jing; Cui, Wen-Ying; Ji, Dan-Ying; Zhang, Yue; Liu, Wen-Hu

2011-01-01

Following the introduction of modified cellulosic and then synthetic membrane dialyzers, it was realized that the dialyzer bio-incompatibility depends on the membrane composition. We designed a prospective, randomized, cohort study of 6 months to determine several parameters of biocompatibility in maintenance hemodialysis (MHD) patients treated with four different membrane dialyzers. There were 60 MHD patients enrolled in the study. In baseline, synthetic low-flux dialyzer, polysulfone (PS) membrane was used in all patients for at least 3 months. Then the patients were randomly divided into three groups according to different dialyzer membranes. Synthetic high-flux dialyzer group, polyethersulfone membrane, cellulose triacetate (CTA) high-flux membrane, and synthetic low-flux dialyzer, polymethylmethacrylate (PMMA) membrane were used in 6 months. A new dialyzer was used for each study treatment, and there was no dialyzer reuse. The biocompatibility markers and solutes removal markers were detected repeatedly at different time points. The blood levels of highly sensitive C reactive protein, interleukin (IL)-1β, and interleukin (IL)-13 showed no difference among different groups at al time points. However, the blood complement levels and white blood cell counts were significantly different among three groups. When the dialyzers changed from PS to PMMA membrane, C3a levels and white blood cell counts changed significantly (p < 0.05). Moreover, the changes of C5a levels were significantly different between group CTA and group PMMA in month 3 (p < 0.05). There were much more differences on bio-incompatibility among different dialyzer membranes.

Influence of blood flow on adsorption of beta2-microglobulin onto AN69 dialyzer membrane.

PubMed

Kandus, A; Malovrh, M; Bren, A F

1997-08-01

Adsorption onto the dialyzer membrane is a contributing factor to the elimination of beta2-microglobulin (beta2M) from the sera of uremic patients. The purpose of this prospective study was to ascertain the influence of the blood flow rate on adsorption of beta2M onto the polyacrylonitrile (AN69) hollow-fiber dialyzer membrane in 8 patients during regular hemodialysis (HD). Blood first passed through a low-flux polysulfone dialyzer and then through an AN69 dialyzer, which was not in contact with the dialysis fluid. During the investigation period (first hour of the HD session), the blood flow rate was 100 ml/ min (first part of the study), 200 ml/min (second part of the study), and 300 ml/min (third part of the study). Ultrafiltration was not performed during the investigation period. At the start of the HD sessions, the serum concentration of beta2M in the afferent blood line did not differ significantly among the 3 parts of the study. Serum beta2M was measured in samples taken from the afferent and efferent blood lines of the AN69 dialyzer at 5, 10, 15, 30, 45, and 60 min. The serum beta2M concentration decreased significantly in blood that had passed through the AN69 dialyzer. This decrease, indicating membrane adsorption, was maximal during the first part and minimal during the third part of study. The decrease in the contact time between the blood and the AN69 could be the underlying cause. The calculated quantities of beta2M adsorbed onto the AN69 membrane (44.2 +/- 10.2, 43.2 +/- 12.1, and 42.6 +/- 17.3 mg) did not differ significantly among the 3 parts of the study. These results suggest that an increase in blood flow rate from 100 to 300 ml/min did not significantly affect the quantity of beta2M adsorbed onto the AN69 membrane.

The Choice of Hemodialysis Membrane Affects Bisphenol A Levels in Blood

PubMed Central

Bosch-Panadero, Enrique; Sanchez-Ospina, Didier; Camarero, Vanesa; Pérez-Gómez, Maria V.; Saez-Calero, Isabel; Abaigar, Pedro; Ortiz, Alberto; Egido, Jesus; González-Parra, Emilio

2016-01-01

Bisphenol A (BPA), a component of some dialysis membranes, accumulates in CKD. Observational studies have linked BPA exposure to kidney and cardiovascular injury in humans, and animal studies have described a causative link. Normal kidneys rapidly excrete BPA, but insufficient excretion may sensitize patients with CKD to adverse the effects of BPA. Using a crossover design, we studied the effect of dialysis with BPA-containing polysulfone or BPA-free polynephron dialyzers on BPA levels in 69 prevalent patients on hemodialysis: 28 patients started on polysulfone dialyzers and were switched to polynephron dialyzers; 41 patients started on polynephron dialyzers and were switched to polysulfone dialyzers. Results were grouped for analysis. Mean BPA levels increased after one hemodialysis session with polysulfone dialyzers but not with polynephron dialyzers. Chronic (3-month) use of polysulfone dialyzers did not significantly increase predialysis serum BPA levels, although a trend toward increase was detected (from 48.8±6.8 to 69.1±10.1 ng/ml). Chronic use of polynephron dialyzers reduced predialysis serum BPA (from 70.6±8.4 to 47.1±7.5 ng/ml, P<0.05). Intracellular BPA in PBMCs increased after chronic hemodialysis with polysulfone dialyzers (from 0.039±0.002 to 0.043±0.001 ng/106 cells, P<0.01), but decreased with polynephron dialyzers (from 0.045±0.001 to 0.036±0.001 ng/106 cells, P<0.01). Furthermore, chronic hemodialysis with polysulfone dialyzers increased oxidative stress in PBMCs and inflammatory marker concentrations in circulation. In vitro, polysulfone membranes released significantly more BPA into the culture medium and induced more cytokine production in cultured PBMCs than did polynephron membranes. In conclusion, dialyzer BPA content may contribute to BPA burden in patients on hemodialysis. PMID:26432902

The influence of dialyzer geometry on blood coagulation and biocompatibility.

PubMed

Lins, L E; Boberg, U; Jacobson, S H; Kjellstrand, C; Ljungberg, B; Skröder, R

1993-11-01

The influence of dialyzer geometry on blood coagulation, heparin requirement and complement activation was studied in fourteen chronic hemodialysis patients. Each patient was dialyzed with two different cuprophan dialyzers, hollow fiber GF 120M and parallel plate Lundia IC5N. Both dialyzers had a wall thickness of 11 microns, surface area of 1.2 m2 and both were sterilized with ethylene oxide. Heparin doses were individually titrated. The mean heparin dose was 6089 +/- 988 U. Platelet count decreased from 218 x 10(9)/l to 193 x 10(9)/l and from 235 x 10(9)/l to 197 x 10(9)/l respectively (hollow fiber/plate dialyzer, ns). The number of leucocytes decreased at 15 min after start of dialysis by 56% and 61% (hollow fiber/plate dialyzer, ns). The heparin requirement, measured as prolongation of whole blood activated coagulation time after identical doses of heparin, were the same in hollow fiber and plate dialysis sessions. The arterial fibrinopeptide A concentrations increased during dialysis from 5.4 to 7.1 nmol/l and 8.5 to 9.6 nmol/l respectively (hollow fiber/plate dialyzer, ns). The residual blood volume in the hollow fiber dialyzers was 1.3 +/- 1.1 ml and in the plate dialyzers 1.5 +/- 0.9 ml (ns). C3a activation, indicated by a marked arterio-venous difference, was observed at 15 min after start of dialysis with hollow fiber as well as plate dialyzers. The arterio-venous difference was less pronounced at the end of dialysis. There were no differences in C3a activation between hollow fiber and plate dialyzers at any timepoint. It is concluded that dialyzer geometry does not significantly influence platelet count, blood coagulation, heparin requirement or complement activation.

Effect of formaldehyde/bleach reprocessing on in vivo performances of high-efficiency cellulose and high-flux polysulfone dialyzers.

PubMed

Murthy, B V; Sundaram, S; Jaber, B L; Perrella, C; Meyer, K B; Pereira, B J

1998-03-01

Among the several disadvantages of reprocessed dialyzers is the concern that reuse could decrease the clearance of uremic toxins, leading to a decrease in the delivered dose of dialysis. To examine this possibility in the clinical setting, the clearances of small molecular weight solutes (urea and creatinine) and middle molecular weight substances (beta 2 microglobulin) were compared during dialysis with "high-efficiency" cellulose (T220L) and "high-flux" polysulfone (F80B) dialyzers reprocessed with formaldehyde and bleach. In a crossover study, six chronic hemodialysis patients were alternately assigned to undergo 21 dialysis treatments with a single T220L dialyzer or F80B dialyzer. Each patient was studied during first use (0 reuse), 2nd reuse (3rd use), and 5th, 10th, 15th, and 20th reuse of each dialyzer. Urea, creatinine, and beta 2 microglobulin clearances were measured at blood flow rates of 300 ml/min (Qb 300) and 400 ml/min (Qb 400). Total albumin loss into the dialysate was measured during each treatment. Urea or creatinine clearance of new T220L dialyzers was not significantly different from that of new F80B dialyzers at either Qb. Urea clearance of F80B dialyzers at Qb 300 decreased from 241 +/- 2 ml/min for new dialyzers to 221 +/- 5 ml/min after 20 reuses (P < 0.001), and Qb 400 from 280 +/- 4 ml/min for new dialyzers to 253 +/- 7 ml/min after 20 reuses (P = 0.001). Similarly, with reuse, creatinine clearance of F80B dialyzers also decreased at Qb 300 (P = 0.07) and Qb 400 (P = 0.03). In contrast, urea or creatinine clearance of T220L dialyzers did not decrease with reuse at either Qb. Urea clearance of T220L dialyzers was significantly higher than that of F80B at Qb 300 at the 5th, 10th, 15th, and 20th reuse (P < 0.001, = 0.005, = 0.004, and = 0.006, respectively), and Qb 400 at the 2nd, 5th, 10th, 15th, and 20th reuse (P = 0.04, 0.008, 0.03, 0.02, and 0.008, respectively). Beta 2 microglobulin clearance of T220L dialyzers was < 5.0 ml/min across the reuses studied. Beta 2 microglobulin clearance of F80B was < 5.0 ml/min for new dialyzers, but increased to 21.2 +/- 5.3 ml/min (Qb 300) and 23.6 +/- 3.3 ml/min (Qb 400) after 20 reuses (P < 0.001). Throughout the study, albumin was undetectable in the dialysate with T220L dialyzers. With F80B dialyzers, albumin was detected in the dialysate in four instances (total loss during dialysis, 483 mg to 1.467 g). In summary, the results of this study emphasize the greater need for information on dialyzer clearances during clinical dialysis, especially with reprocessed dialyzers. A more accurate knowledge of dialyzer performance in vivo would help to ensure that the dose of dialysis prescribed is indeed delivered to the patients.

Dialyzer reuse--part II: advantages and disadvantages.

PubMed

Twardowski, Zbylut J

2006-01-01

Although single dialyzer use and reuse by chemical reprocessing are both associated with some complications, there is no definitive advantage to either in this respect. Some complications occur mainly at the first use of a dialyzer: a new cellophane or cuprophane membrane may activate the complement system, or a noxious agent may be introduced to the dialyzer during production or generated during storage. These agents may not be completely removed during the routine rinsing procedure. The reuse of dialyzers is associated with environmental contamination, allergic reactions, residual chemical infusion (rebound release), inadequate concentration of disinfectants, and pyrogen reactions. Bleach used during reprocessing causes a progressive increase in dialyzer permeability to larger molecules, including albumin. Reprocessing methods without the use of bleach are associated with progressive decreases in membrane permeability, particularly to larger molecules. Most comparative studies have not shown differences in mortality between centers reusing and those not reusing dialyzers, however, the largest cluster of dialysis-related deaths occurred with single-use dialyzers due to the presence of perfluorohydrocarbon introduced during the manufacturing process and not completely removed during preparation of the dialyzers before the dialysis procedure. The cost savings associated with reuse is substantial, especially with more expensive, high-flux synthetic membrane dialyzers. With reuse, some dialysis centers can afford to utilize more efficient dialyzers that are more expensive; consequently they provide a higher dose of dialysis and reduce mortality. Some studies have shown minimally higher morbidity with chemical reuse, depending on the method. Waste disposal is definitely decreased with the reuse of dialyzers, thus environmental impacts are lessened, particularly if reprocessing is done by heat disinfection. It is safe to predict that dialyzer reuse in dialysis centers will continue because it also saves money for the providers. Saving both time for the patient and money for the provider were the main motivations to design a new machine for daily home hemodialysis. The machine, developed in the 1990s, cleans and heat disinfects the dialyzer and lines in situ so they do not need to be changed for a month. In contrast, reuse of dialyzers in home hemodialysis patients treated with other hemodialysis machines is becoming less popular and is almost extinct.

Lyophilization decreases the formation of dialyzable iron by extraction and digestion of chicken breast muscle.

PubMed

Karava, Nilesh B; Mahoney, Raymond R

2011-06-01

We studied the effect of lyophilization of chicken breast muscle on the formation of dialyzable iron from ferric iron. Chicken breast muscle was used chilled, frozen or lyophilized and was analyzed for sulfhydryl and histidine content. It was then homogenized and mixed with ferric iron. The mixture was extracted with acid or digested with pepsin and pancreatin. The extracts and digests were analyzed for dialyzable ferrous and dialyzable total iron and also for protein. In the chilled muscle, similar amounts of dialyzable iron were formed after acid extraction and after proteolytic digestion; however, digestion led to more dialyzable ferrous iron. Freezing had no effect but lyophilization of the homogenized muscle caused large decreases in dialyzable iron and dialyzable ferrous iron for both extraction and digestion processes. Lyophilization also resulted in decreased extraction of peptides, decreased digestion of muscle proteins and reduced levels of sulfhydryl and histidine residues. Our results demonstrate that dialyzable iron is produced both by acid-soluble low molecular weight muscle component(s) and also by peptides resulting from digestion of muscle proteins: both of which reduce and chelate iron. Reduced formation of dialyzable iron by both mechanisms following lyophilization could be explained by sulfhydryl oxidation and impaired digestion due to protein crosslinking.

Effect of dialyzer geometry on granulocyte and complement activation.

PubMed

Schaefer, R M; Heidland, A; Hörl, W H

1987-01-01

During hemodialysis with cuprophan membranes, the complement system as well as leukocytes become activated. In order to clarify the role of dialyzer geometry, the effect of hollow-fiber versus flat-sheet dialyzers and of different surface areas on C3a generation and leukocyte degranulation was investigated. Plasma levels of leukocyte elastase in complex with alpha 1-proteinase inhibitor were significantly increased after 1 h (+55%) and 3 h (+62%) of hemodialysis with flat-sheet dialyzers as compared to hollow-fiber devices. In addition, plasma levels of lactoferrin, released from the specific granules of leukocytes during activation, were significantly higher (+42%) 3 h after the onset of dialysis treatment with flat-sheet than with hollow-fiber dialyzers. With respect to surface area, larger dialyzers tended to cause more release of leukocyte elastase as compared to dialyzers with smaller surface areas, irrespectively of the configuration of the dialyzer used. On the other hand, activation of the complement system, as measured by the generation of C3a-desarg, did not differ with both types of configurations. The same held true for leukopenia, which was almost identical for hollow-fiber and flat-sheet dialyzers. From these findings two lines of evidence emerge: First, not only the type of membrane material used in a dialyzer may influence its biocompatibility, but the geometry of the extracorporeal device also determines the degree of compatibility. Hence, the extent of leukocyte activation correlated with both configuration of the dialyzer and surface area of the membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Reuse and Biocompatibility of Hemodialysis Membranes: Clinically Relevant?

PubMed

Upadhyay, Ashish; Jaber, Bertrand L

2017-03-01

The practice of reprocessing dialyzers for reuse, once predominant in the United States, has been steadily declining over the last 20 years. The professed roles of reuse in improving dialyzer membrane biocompatibility and lowering the risk of first-use syndrome have lost relevance with the advent of biocompatible dialyzer membranes and favorable sterilization techniques. The potential for cost-savings from reuse is also called into question by the easy availability of comparatively cheaper dialyzers and rising regulatory demands and operational cost of reprocessing systems. While the environmental concerns from additional dialyzer-related solid waste from rising single-use practice remains pertinent and requires development of safer dialyzer disposable system technologies, there is no meaningful medical rationale for the continued practice of dialyzer reuse in the twenty-first century. © 2017 Wiley Periodicals, Inc.

Construction of a liposome dialyzer for the preparation of high-value, small-volume liposome formulations.

PubMed

Adamala, Katarzyna; Engelhart, Aaron E; Kamat, Neha P; Jin, Lin; Szostak, Jack W

2015-06-01

The liposome dialyzer is a small-volume equilibrium dialysis device, built from commercially available materials, that is designed for the rapid exchange of small volumes of an extraliposomal reagent pool against a liposome preparation. The dialyzer is prepared by modification of commercially available dialysis cartridges (Slide-A-Lyzer cassettes), and it consists of a reactor with two 300-μl chambers and a 1.56-cm(2) dialysis surface area. The dialyzer is prepared in three stages: (i) disassembling the dialysis cartridges to obtain the required parts, (ii) assembling the dialyzer and (iii) sealing the dialyzer with epoxy. Preparation of the dialyzer takes ∼1.5 h, not including overnight epoxy curing. Each round of dialysis takes 1-24 h, depending on the analyte and membrane used. We previously used the dialyzer for small-volume non-enzymatic RNA synthesis reactions inside fatty acid vesicles. In this protocol, we demonstrate other applications, including removal of unencapsulated calcein from vesicles, remote loading and vesicle microscopy.

Polyphenol bioavailability in nuts and seeds by an in vitro dialyzability approach.

PubMed

Herbello-Hermelo, Paloma; Lamas, Juan Pablo; Lores, Marta; Domínguez-González, Raquel; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2018-07-15

An in vitro dialyzability approach has been undertaken to elucidate the bioavailable fraction of the total polyphenols (TPs) of edible nuts and seeds. The TP contents in samples and in dialyzates were assessed by the Folin-Ciocalteu spectrophotometric method. Antioxidant activity was determined in selected samples, using a modified method against Trolox®. TPs and antioxidant activity in nuts/seeds were determined after applying a pressurized liquid extraction sample pre-treatment. High dialyzability ratios were assessed in most nuts/seeds (TP dialyzability percentages within the 25-91% range). The highest TP dialyzability ratios were found in raw Brazil nuts (81 ± 5%), toasted pistachios (88 ± 9%), and fried cashews (89 ± 9%), whereas TPs in pumpkin seeds were found to be very low (TPs were not detected in the dialyzable fraction). TP dialyzability was correlated with the copper content in nuts and seeds. Copyright © 2018 Elsevier Ltd. All rights reserved.

[The treatment of hyperhomocysteinemia in patients on dialysis: folic acid or the high-flow polysulphonic membrane?].

PubMed

Lovcić, Vesna; Kes, Petar; Zeljko, Reiner; Kusec, Vesna

2006-06-01

The aim of the study was to determine the effects of high-flow and low-flow hemodialysis (HD), with simultaneous treatment with folic acid and vitamin B12, on total homocysteine (tHcy) concentration in plasma of dialyzed patients. The planned clinical observation included 46 patients of both sexes, aged 21-82, treated with bicarbonate dialysis for a mean of 4.7 years. The patients were divided into group A, subsequently dialyzed by use of high-flow polysulphonic membrane (AN 69ST, Nephral 300), and group B that continued to be dialyzed by use of low-flow diacetate membrane (Diacepal 14 and 16). The subjects in both groups received 30 mg of folic acid at the end of each dialysis (3 times a week), and 500 g of vitamin B12 at the end of every other dialysis. The method of stable isotopic dilution mass spectrometry was used to measure tHcy. Folic acid was determined by the test based on ion capture technology. Vitamin B12 was determined by MEIA. An increase in the concentration of tHcy was observed in 39/46 (85%) patients with a mean concentration of 24.76 +/- 11.04 micromol/L. The mean concentration of folic acid and vitamin B12 was within the normal limits. In the group dialyzed by high-flow dialyzer, the values of tHcy and folic acid decreased (18.74 +/- 2.95 micromol/L and 13.90 +/- 6.78 pmol/L) after hemodialysis, which was significant compared to the initial value (p<0.01 and p<0.05, respectively). At four weeks of treatment, tHcy concentration before HD showed a significant decrease both in the group dialyzed by high-flow dialyzer (15.10 +/- 4.26 mmol/L, p<0.01) and in the group dialyzed by low-flow dialyzer (12.54 +/- 3.87 micromol/L, p<0.01) compared to the measure before HD and before the treatment. There was no statistically significant difference (z -0.40, p>0.68) in the percentage of tHcy change between the group treated by high-flow dialyzer and the group treated by low-flow dialyzer in the measurements before HD and before the treatment with folic acid and vitamin B12, and after the treatment. There is a literature report on the concentration increase by 26 micromol/L, which is very similar to our result. The absence of long-term effect on predialysis concentration of tHcy in HD by high-flow membrane has also been described, because the decrease of tHcy is mantained until the uremic toxins, enzyme inhibitors that are necessary for the process of remethylation of Hcy, accumulated again. During high-flow HD, the folic acid concentration decreased by 23.05% on an average, consistent with other literature reports. Some reports support our observation that the dosage of folic acid required for tHcy decrease is 15-30 mg, and that the dosage higher than 60 mg does not significantly decrease tHcy concentration. Our study confirmed the reported observations that treatment with folic acid and vitamin B12 rather than high-flow dialyzer contributes to tHcy decrease. The study confirmed the high prevalence of hyperhomocysteinemia in patients on dialysis. The treatment with folic acid and vitamin B12 results in a significant decrease of tHcy. After individual HD by high-flow dialyzer, there is a significant, but temporary decrease of tHcy concentration in plasma. There is no significant difference in the efficiency on pre-dialysis tHcy concentration between the high-flow and low-flow dialyzer membrane. Because of the atherogenic effect of hyperhomocysteinemia, the treatment with folic acid and vitamin B12 should be accepted as an options to lower the risk factors for the rapid atherosclerosis in patients on dialysis, thus reducing the occurrence and fatality of cardiovascular diseases.

Efficacy of vitamin E-bonded polysulfone dialyzer and polysulfone dialyzer on a series of non-anticoagulant hemodialysis.

PubMed

Torato, Toshihiro; Doi, Kent; Negishi, Kousuke; Hamasaki, Yoshifumi; Satonaka, Hiroshi; Hanafusa, Norio; Noiri, Eisei

2013-01-01

Non-anticoagulant hemodialysis is conducted occasionally at limited numbers of hospitals on an empirical basis. This study examines the efficacy of polysulfone and vitamin E-bonded polysulfone dialyzer for non-anticoagulant hemodialysis. These dialyzers were assigned one after the other for a vintage hemodialysis patient complicated with uncontrollable bleeding. The patient's vital and console data throughout non-anticoagulant hemodialysis were monitored serially. Both dialyzers were reasonably applicable to hemodialysis without major clotting. The scheduled treatment period was completed. Vitamin E-bonded polysulfone dialyzer was superior to non-anticoagulant hemodialysis based on venous pressure observed during treatment.

Beta 2-microglobulin kinetics in maintenance hemodialysis: a comparison of conventional and high-flux dialyzers and the effects of dialyzer reuse.

PubMed

DiRaimondo, C R; Pollak, V E

1989-05-01

beta 2-Microglobulin (beta 2M) forms synovial and bony amyloid deposits in long-term hemodialysis patients. To define the kinetics of beta 2M during hemodialysis and the effects of dialyzer reprocessing, we measured serum beta 2M, plasma C3a, and neutrophil counts immediately predialysis; 15, 90, and 180 minutes after beginning dialysis; and 15 minutes postdialysis in ten chronic hemodialysis patients. The studies were performed during first and third uses of cuprammonium rayon and polysulfone dialyzers processed by rinsing with water, then bleach, in an automated system (Seratronics DRS 4) and then packed in 1.5% formaldehyde. Mean serum beta 2M (corrected for ultrafiltration) decreased by 16.6% +/- 18.1% with new cuprammonium dialyzers and 57.1% +/- 12.8% with new polysulfone dialyzers. Dialyzer reprocessing had no significant effect on this decline. Predialysis serum beta 2M decreased by 30.4% +/- 15.5% 1 month after switching from cuprammonium to polysulfone dialyzers; these levels remained stable after 3 months of dialysis with polysulfone. Complement activation and neutropenia during dialysis were significantly more marked with cuprammonium, but were not affected by reprocessing of either dialyzer. In vitro adsorption of 124I-beta 2M to polysulfone fibers was greater than to cuprammonium; adsorption was not influenced by dialyzer reprocessing.

Influence of the dialyzer membrane material on sodium transport in hemodialysis.

PubMed

Lopot, F; Kotyk, P; Bláha, J; Válek, A

1995-11-01

Traditionally Gibbs-Donnan coefficients based on the mean charge of plasma proteins are used as the only correction factor in equations describing sodium transport across the dialyzer membrane. This ignores the possible impact of the membrane material. Correction coefficients (CC) of the whole dialyzer were measured during in vivo dialysis as a quotient of dialysate to plasma sodium in an equilibrated state for different membrane materials used in commercially available dialyzers. Their mean value and correlation with total plasma protein content (TPP) were evaluated. CC for the six materials evaluated differed both in the intercept and slope of the regression line CC versus TPP: Cuprophan 1: CC = 1.0253 - 0.00017 x TPP; Hemophan 1: CC = 1.119 - 0.00175 x TPP; Hemophan 2: CC = 1.095 - 0.00111 x TPP; PMMA: CC = 1.0353 - 0.00044 x TPP; SCE:CC = 1.114 - 0.00145 x TPP; and Cuprophan 1:CC = 1.0562 - 0.00065 x TPP. The observed differences are attributed to the different charge densities of the membrane materials and suggest that for a precise description of sodium transport, the role of the membrane material needs to be considered.

Vitamin E-coated dialyzer membranes downregulate expression of monocyte adhesion and co-stimulatory molecules.

PubMed

Betjes, Michiel G H; Hoekstra, Franciska M E; Klepper, M; Postma, Saskia M; Vaessen, Leonard M B

2004-01-01

In patients on chronic hemodialysis leukocyte activation has been related to the impaired function of the immune system. In this study we investigated if the vitamin E-coated dialyzer membrane could reduce monocyte activation thereby improving cellular immunity. This hypothesis was tested in a prospective crossover trial in which 14 stable hemodialysis patients were switched from the baseline hemophane dialyzer to a vitamin E-coated and thereafter a polysulphone dialyzer membrane or vice versa. Monocyte MHC class I, CD54 and ICAM-1 expression was significantly downregulated when a vitamin E-coated or polysulphone dialyzer was used. The use of a vitamin E membrane specifically decreased monocyte CD40 and CD86 expression. Lectin induced T cell proliferation increased with the use of the vitamin E-coated membrane as compared to polysulphone and hemophane dialyzers. Vitamin E-coated dialyzers induced a less-activated phenotype of monocytes and may improve cellular immunity.

Cooking Chicken Breast Reduces Dialyzable Iron Resulting from Digestion of Muscle Proteins

PubMed Central

Gokhale, Aditya S.; Mahoney, Raymond R.

2014-01-01

The purpose of this research was to study the effect of cooking chicken breast on the production of dialyzable iron (an in vitro indicator of bioavailable iron) from added ferric iron. Chicken breast muscle was cooked by boiling, baking, sautéing, or deep-frying. Cooked samples were mixed with ferric iron and either extracted with acid or digested with pepsin and pancreatin. Total and ferrous dialyzable iron was measured after extraction or digestion and compared to raw chicken samples. For uncooked samples, dialyzable iron was significantly enhanced after both extraction and digestion. All cooking methods led to markedly reduced levels of dialyzable iron both by extraction and digestion. In most cooked, digested samples dialyzable iron was no greater than the iron-only (no sample) control. Cooked samples showed lower levels of histidine and sulfhydryls but protein digestibility was not reduced, except for the sautéed sample. The results showed that, after cooking, little if any dialyzable iron results from digestion of muscle proteins. Our research indicates that, in cooked chicken, residual acid-extractable components are the most important source of dialyzable iron. PMID:26904627

Bioavailability assessment of essential and toxic metals in edible nuts and seeds.

PubMed

Moreda-Piñeiro, Jorge; Herbello-Hermelo, Paloma; Domínguez-González, Raquel; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2016-08-15

Bioavailability of essential and toxic metals in edible nuts and seeds has been assessed by using an in vitro dialyzability approach. The samples studied included walnuts, Brazil nuts, Macadamia nuts, pecans, hazelnuts, chestnuts, cashews, peanuts, pistachios and seeds (almond, pine, pumpkin and sunflower). Metals were measured by inductively coupled plasma-mass spectrometry in dialyzates and also in samples after a microwave assisted acid digestion pre-treatment. Low dialyzability percentages were found for Al, Fe and Hg; moderate percentages were found for Ba, Ca, Cd, Co, Cu, K, Li, Mg, Mn, Mo, P, Pb, Se, Sr, Tl and Zn; and high dialyzability ratios were found for As, Cr and Ni. The highest dialyzability percentages were found in raw chestnuts and raw hazelnuts. Metal dialyzability was found to be negatively affected by fat content. Positive correlation was found between carbohydrate content and metal dialyzability ratios. Protein and dietary fibre content did not influence metal bioavailability. Predicted dialyzability for some metals based on fat and protein content could also be established. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cooking Chicken Breast Reduces Dialyzable Iron Resulting from Digestion of Muscle Proteins.

PubMed

Gokhale, Aditya S; Mahoney, Raymond R

2014-01-01

The purpose of this research was to study the effect of cooking chicken breast on the production of dialyzable iron (an in vitro indicator of bioavailable iron) from added ferric iron. Chicken breast muscle was cooked by boiling, baking, sautéing, or deep-frying. Cooked samples were mixed with ferric iron and either extracted with acid or digested with pepsin and pancreatin. Total and ferrous dialyzable iron was measured after extraction or digestion and compared to raw chicken samples. For uncooked samples, dialyzable iron was significantly enhanced after both extraction and digestion. All cooking methods led to markedly reduced levels of dialyzable iron both by extraction and digestion. In most cooked, digested samples dialyzable iron was no greater than the iron-only (no sample) control. Cooked samples showed lower levels of histidine and sulfhydryls but protein digestibility was not reduced, except for the sautéed sample. The results showed that, after cooking, little if any dialyzable iron results from digestion of muscle proteins. Our research indicates that, in cooked chicken, residual acid-extractable components are the most important source of dialyzable iron.

Comparative crossover controlled study using polysulphone and vitamin E coated dialyzers.

PubMed

Al-Jondeby, Mohamed S; Cabaguing, Iolani T; Pajarillo, Amelita A; Hawas, Fahd A; Mousa, Dujanah H; Al-Sulaiman, Mohamed H; Shaheen, Faissal A; Al-Khader, Abdulla A

2003-03-01

There is relatively little clinical experience reported on the use of the vitamin E coated dialyzer (CL-EE12, Terumo). This study compares its efficacy and intradialytic symptoms with a polysulphone dialyzer in 2 groups of patients in a controlled crossover trial design. This study was carried out at the Armed Forces Hospital, Riyadh, Kingdom of Saudi Arabia, during the time period January to March 2002. In group A, 34 patients were dialyzed for 4 weeks with vitamin E dialyzer then switched over to Fresenius 60 (F60) for 4 weeks. In group B, 41 patients were dialyzed with F60 for 4 weeks then switched to vitamin E coated dilayzers for 4 weeks. The following parameters were measured weekly, hemoglobin level, urea reduction ratio (URR), urea clearance ratio (Kt/V), pre and post dialysis diastolic blood pressure (DBP) and systolic blood pressure (SBP), interdialytic weight gain. The patients were observed for interdialytic hypotension or symptoms. No significant findings were found in any of the parameters except more dialyzer clotting was observed with vitamin E dialyzer than in F60 dialyzers (1.6% of dialysis sessions versus 0.1% P<0.03). The interdialytic weight gain tended to be less in the vitamin E group but did not reach statistically significant difference. The Kt/V and URR were slightly higher when using the vitamin E dialyzer only in the second and third weeks. hypotensive episodes (P<.007) less leg cramp (P<.31) and less itching (P<.02) in the vitamin E coated treated group within group B. There were only minor differences noted between the 2 dialyzers in the parameters measured.

Do clinical outcomes in chronic hemodialysis depend on the choice of a dialyzer?

PubMed

Ward, Richard A

2011-01-01

Nephrologists are presented with a range of choices when selecting a dialyzer for chronic hemodialysis. Dialyzers differ in the material, structure, permeability and surface area of their membrane, and how the dialyzer is sterilized. Opinions vary regarding the impact of dialyzer characteristics on patient outcomes and which, if any, of these properties to take into account when choosing a dialyzer can be confusing. In the general dialysis population, there is no compelling evidence that the choice of a membrane material from among those materials currently in clinical use has a significant impact on morbidity or mortality (although there are rare patients who will react adversely to a given dialysis membrane). Similarly, most dialyzers are capable of adequately removing small solutes, such as urea, provided they are used with an appropriate blood flow rate and treatment time to ensure delivery of a single-pool Kt/V(urea) of at least 1.25 for men and 1.65 for women. However, in some dialysis patient subpopulations, the results of randomized clinical trials suggest that use of dialyzer containing high-flux membranes confers an outcome advantage. The extent to which this advantage is realized might also depend on how the dialyzer is used, with application in convective therapies such as hemodiafiltration being superior to diffusive therapies such as hemodialysis. This possibility is currently the subject of several large clinical trials. © 2011 Wiley Periodicals, Inc.

Construction of a Liposome Dialyzer for preparation of high-value, small-volume liposome formulations

PubMed Central

Adamala, Katarzyna; Engelhart, Aaron E.; Kamat, Neha P.; Jin, Lin; Szostak, Jack W.

2016-01-01

The liposome dialyzer is a small-volume equilibrium dialysis device, built from commercially available materials, that is designed for rapid exchange of small volumes of an extraliposomal reagent pool against a liposome preparation. The dialyzer is prepared by modification of commercially available dialysis cartridges and consists of a reactor with two 300 µL chambers and a 1.56 cm2 dialysis surface area. The dialyzer is prepared in three stages: 1) disassembly of dialysis cartridges to obtain required parts; 2) assembly of the dialyzer; and 3) sealing the dialyzer with epoxy. Preparation of the dialyser takes about 1.5 h, not including overnight epoxy curing. Each round of dialysis takes 1–24 h, depending on the analyte and membrane employed. We previously used the dialyzer for small-volume nonenzymatic RNA synthesis reactions inside fatty acid vesicles. In this protocol, we demonstrate other applications, including removal of unencapsulated calcein from vesicles, remote loading, and vesicle microscopy. PMID:26020615

Effect of vitamin E-bonded dialyzer on eosinophilia in haemodialysis patients.

PubMed

Kojima, Kenichiro; Oda, Kuniyoshi; Homma, Hitoshi; Takahashi, Kazushi; Kanda, Yoshiko; Inokami, Taketoshi; Uchida, Shunya

2005-09-01

Eosinophilia in haemodialysis patients probably results from allergy to haemodialysis-related materials, including dialyzer membranes. We examined the effects of vitamin E-bonded dialyzers on eosinophil counts in haemodialysis patients. We enrolled seven patients who were on regular haemodialysis and had sustained eosinophilia. White blood cell, eosinophil, CD4- and CD8-positive lymphocyte counts, and serum interleukin-5 (IL-5) and IgE levels were determined before, 2 and 4 weeks after switching to vitamin E-bonded dialyzers. Eosinophil and CD4-positive lymphocyte counts and serum IL-5 were significantly (P = 0.003, 0.003 and 0.031, respectively) decreased after switching to vitamin E-bonded dialyzers. CD8-positive lymphocyte counts and serum IgE levels were unaltered. Crossover tests in two cases reproduced the higher eosinophilia within 4 weeks after returning to the original non-vitamin E-bonded dialyzer. Vitamin E-bonded dialyzers may ameliorate eosinophilia through a mechanism mediated by a decrease in IL-5 secretion by CD4-positive lymphocytes.

Performance of hemodialysis with novel medium cut-off dialyzers

PubMed Central

Lyko, Raphael; Nilsson, Lars-Göran; Beck, Werner; Amdahl, Michael; Lechner, Petra; Schneider, Andreas; Wanner, Christoph; Rosenkranz, Alexander R.; Krieter, Detlef H.

2017-01-01

Background. Compared to high-flux dialysis membranes, novel medium cut-off (MCO) membranes show greater permeability for larger middle molecules. Methods. In two prospective, open-label, controlled, randomized, crossover pilot studies, 39 prevalent hemodialysis (HD) patients were studied in four dialysis treatments as follows: study 1, three MCO prototype dialyzers (AA, BB and CC with increasing permeability) and one high-flux dialyzer in HD; and study 2, two MCO prototype dialyzers (AA and BB) in HD and high-flux dialyzers in HD and hemodiafiltration (HDF). Primary outcome was lambda free light chain (λFLC) overall clearance. Secondary outcomes included overall clearances and pre-to-post-reduction ratios of middle and small molecules, and safety of MCO HD treatments. Results. MCO HD provided greater λFLC overall clearance [least square mean (standard error)] as follows: study 1: MCO AA 8.5 (0.54), MCO BB 11.3 (0.51), MCO CC 15.0 (0.53) versus high-flux HD 3.6 (0.51) mL/min; study 2: MCO AA 10.0 (0.58), MCO BB 12.5 (0.57) versus high-flux HD 4.4 (0.57) and HDF 6.2 (0.58) mL/min. Differences between MCO and high-flux dialyzers were consistently significant in mixed model analysis (each P < 0.001). Reduction ratios of λFLC were greater for MCO. Clearances of α1-microglobulin, complement factor D, kappa FLC (κFLC) and myoglobin were generally greater with MCO than with high-flux HD and similar to or greater than clearances with HDF. Albumin loss was moderate with MCO, but greater than with high-flux HD and HDF. Conclusions. MCO HD removes a wide range of middle molecules more effectively than high-flux HD and even exceeds the performance of high-volume HDF for large solutes, particularly λFLC. PMID:27587605

THE REGULATORY ROLE OF DIVALENT CATIONS IN HUMAN GRANULOCYTE CHEMOTAXIS

PubMed Central

Gallin, John I.; Rosenthal, Alan S.

1974-01-01

Optimal human granulocyte chemotaxis has been shown to require both calcium and magnesium. Exposure of granulocytes to three different chemotactic factors (C5a, kallikrein, and dialyzable transfer factor) yielded a rapid calcium release, depressed calcium uptake, and was associated with a shift of calcium out of the cytoplasm and into a granule fraction. Colchicine, sodium azide, and cytochalasin B, in concentrations that inhibited chemotaxis, also inhibited calcium release while low concentrations of cytochalasin B, which enhanced chemotaxis, also enhanced calcium release. Microtubule assembly was visualized both in cells suspended in C5a without a chemotactic gradient and in cells actively migrating through a Micropore filter. The data suggest microtubule assembly is regulated, at least, in part, by the level of cytoplasmic calcium. It is proposed that asymmetric assembly of microtubules may be instrumental in imparting the net vector of motion during chemotaxis. PMID:4855032

Dialysis system. [using ion exchange resin membranes permeable to urea molecules

NASA Technical Reports Server (NTRS)

Mueller, W. A. (Inventor)

1978-01-01

The improved hemodialysis system utilizes a second polymeric membrane having dialyzate in contact with one surface and a urea decomposition solution in contact with the other surface. The membrane selectively passes urea from the dialyzate into the decomposition solution, while preventing passage of positively charged metal ions from the dialyzate into the solution and ammonium ions from the solution into the dialyzate.

In vitro evaluation of iron solubility and dialyzability of various iron fortificants and of iron-fortified milk products targeted for infants and toddlers.

PubMed

Kapsokefalou, Maria; Alexandropoulou, Isidora; Komaitis, Michail; Politis, Ioannis

2005-06-01

The objectives of the present study were: to compare the solubility and dialyzability of various iron fortificants (iron pyrophosphate, ferrous bis-glycinate, ferrous gluconate, ferrous lactate, ferrous sulfate) added, in the presence of ascorbic acid, to pasteurized milk samples produced under laboratory conditions; and to compare the solubility and dialyzability of iron in commercial pasteurized, UHT and condensed milk products available in the Greek market fortified with various vitamins and minerals including iron and targeted towards infants (6-12 months old) and toddlers. Iron solubility and dialyzability were determined using a simulated gastrointestinal digestive system. Ferrous dialyzable iron (molecular weight lower than 8000) was used as an index for prediction of iron bioavailability. Ferrous dialyzable iron in pasteurized milk samples fortified with iron pyrophosphate, ferrous lactate and ferrous bis-glycinate was higher (P < 0.05) than that in milk samples fortified with ferrous sulfate and ferrous gluconate. In commercial liquid pasteurized or UHT milk products, formation of ferrous dialyzable iron in products fortified with ferrous lactate was not different (P > 0.05) from those fortified with ferrous sulfate. Ferrous dialyzable iron in four condensed commercial milk products was higher (P < 0.05) than the corresponding values of the liquid UHT milk samples fortified with the same fortificant (ferrous sulfate). Ferrous dialyzable iron was higher (P < 0.05) in products targeted for infants compared with those targeted for toddlers. In conclusion, the type of iron source, milk processing and the overall product composition affect formation of ferrous dialyzable iron and may determine the success and effectiveness of iron fortification of milk.

Randomized controlled open-label trial of vitamin E-bonded polysulfone dialyzer and erythropoiesis-stimulating agent response.

PubMed

Sanaka, Tsutomu; Mochizuki, Takahiro; Kinugasa, Eriko; Kusano, Eiji; Ohwada, Shigeru; Kuno, Tsutomu; Kojima, Kenichiro; Kobayashi, Shuzo; Satoh, Minoru; Shimada, Noriaki; Nakao, Kazushi; Nakazawa, Ryoichi; Nishimura, Hideki; Noiri, Eisei; Shigematsu, Takashi; Tomo, Tadashi; Maeda, Teiryo

2013-06-01

A 1-year multicenter prospective randomized controlled study was conducted on the effects of vitamin E-bonded polysulfone dialyzers on erythropoiesis-stimulating agent response in hemodialysis patients. Major inclusion criteria were use of high-flux polysulfone dialyzers with 50-70 ml/min β2-microglobulin clearance over 3 months, transferrin saturation over 20%, same erythropoiesis-stimulating agent for over 3 months, and hemoglobin at 10-12 g/dl. Hemodialysis patients were placed in four interventional groups: two hemoglobin ranges (10.0-10.9 or 11.0-11.9 g/dl) and two dialyzers. Patients were randomly assigned by central registration to a vitamin E-bonded polysulfone dialyzers or polysulfone control group. Primary end point was relative erythropoiesis resistance index at baseline between groups at 12 months. Erythropoiesis resistance index was defined as total weekly erythropoiesis-stimulating agent dose divided by hemoglobin. There were no statistically significant differences in age or sex. There was no significant difference in relative erythropoiesis resistance index between vitamin E-bonded polysulfone dialyzers and control groups at 12 months (vitamin E-bonded polysulfone dialyzers: 1.1, control: 1.3). The vitamin E-bonded polysulfone dialyzers group showed better relative erythropoiesis resistance index than the control group at 11.0-11.9 g/dl hemoglobin (vitamin E-bonded polysulfone dialyzers: 1.0, control: 1.4 at 12 months, significant difference) but no difference at 10.0-10.9 g/dl hemoglobin. The overall relative erythropoiesis resistance index showed no difference between the vitamin E-bonded polysulfone dialyzers and control groups, although the change in relative erythropoiesis resistance index differed according to hemoglobin level.

Randomized Controlled Open-Label Trial of Vitamin E-Bonded Polysulfone Dialyzer and Erythropoiesis-Stimulating Agent Response

PubMed Central

Mochizuki, Takahiro; Kinugasa, Eriko; Kusano, Eiji; Ohwada, Shigeru; Kuno, Tsutomu; Kojima, Kenichiro; Kobayashi, Shuzo; Satoh, Minoru; Shimada, Noriaki; Nakao, Kazushi; Nakazawa, Ryoichi; Nishimura, Hideki; Noiri, Eisei; Shigematsu, Takashi; Tomo, Tadashi; Maeda, Teiryo

2013-01-01

Summary Background and objectives A 1-year multicenter prospective randomized controlled study was conducted on the effects of vitamin E-bonded polysulfone dialyzers on erythropoiesis-stimulating agent response in hemodialysis patients. Design, setting, participants, & measurements Major inclusion criteria were use of high-flux polysulfone dialyzers with 50–70 ml/min β2-microglobulin clearance over 3 months, transferrin saturation over 20%, same erythropoiesis-stimulating agent for over 3 months, and hemoglobin at 10–12 g/dl. Hemodialysis patients were placed in four interventional groups: two hemoglobin ranges (10.0–10.9 or 11.0–11.9 g/dl) and two dialyzers. Patients were randomly assigned by central registration to a vitamin E-bonded polysulfone dialyzers or polysulfone control group. Primary end point was relative erythropoiesis resistance index at baseline between groups at 12 months. Erythropoiesis resistance index was defined as total weekly erythropoiesis-stimulating agent dose divided by hemoglobin. Results There were no statistically significant differences in age or sex. There was no significant difference in relative erythropoiesis resistance index between vitamin E-bonded polysulfone dialyzers and control groups at 12 months (vitamin E-bonded polysulfone dialyzers: 1.1, control: 1.3). The vitamin E-bonded polysulfone dialyzers group showed better relative erythropoiesis resistance index than the control group at 11.0–11.9 g/dl hemoglobin (vitamin E-bonded polysulfone dialyzers: 1.0, control: 1.4 at 12 months, significant difference) but no difference at 10.0–10.9 g/dl hemoglobin. Conclusions The overall relative erythropoiesis resistance index showed no difference between the vitamin E-bonded polysulfone dialyzers and control groups, although the change in relative erythropoiesis resistance index differed according to hemoglobin level. PMID:23599410

The Sugar Model: Catalytic Flow Reactor Dynamics of Pyruvaldehyde Synthesis from Triose Catalyzed by Poly-L-Lysine Contained in a Dialyzer

NASA Technical Reports Server (NTRS)

Weber, Arthur L.; DeVincenzi, Donald (Technical Monitor)

2000-01-01

The formation of pyruvaldehyde from triose sugars was catalyzed by poly-L-lysine contained in a small dialyzer (100 MWCO) suspended in a much larger triose substrate reservoir. The polylysine confined in the dialyzer functioned as a catalytic flow reactor that constantly brought in triose from the substrate reservoir by diffusion to offset the drop in triose concentration within the reactor caused by its conversion to pyruvaldehyde. A 400 mM solution of poly-L-lysine contained in a 0.35 ml dialyzer placed in a 120 ml solution of triose substrate (pH 5.5, 40 C) generated pyruvaldehyde 11 -times faster than an a control reaction without the catalytic dialyzer. However, since the catalytic dialyzer's volume was 343-times smaller than the control reaction, the synthetic intensity (rate/volume) of pyruvaldehyde synthesis within the catalytic dialyzer was 3400-times greater than that of the control reaction and substrate solution. A similar result was obtained using a dialyzer with a 500 MWCO value. Acting as a catalytic flow reactor the polylysine catalytic dialyzer synthesized about 3.5 molecules of pyruvaldehyde per lysine residue in 7 days -- an amount of triose equal to twice the weight of the catalyst. At 7 days the catalytic activity of polylysine was 16% of its initial value, a result indicating catalyst-poisoning caused by reaction of pyruvaldehyde with the e-amino groups of polylysine. The dialyzer method of catalyst containment was selected it provides a simple, flexible, and easily manipulated experimental system for studying the dynamics and evolutionary development of confined autocatalytic processes related to the origin of life under anaerobic conditions.

Risk factors for selective cognitive decline in dialyzed patients with end-stage renal disease: evidence from verbal fluency analysis.

PubMed

Harciarek, Michał; Williamson, John B; Biedunkiewicz, Bogdan; Lichodziejewska-Niemierko, Monika; Dębska-Ślizień, Alicja; Rutkowski, Bolesław

2012-01-01

Although dialyzed patients often have cognitive problems, little is known about the nature of these deficits. We hypothesized that, in contrast to semantic fluency relying mainly on temporal lobes, phonemic fluency, preferentially depending on functions of frontal-subcortical systems, would be particularly sensitive to the constellation of physiological pathological processes associated with end-stage renal disease and dialysis. Therefore, we longitudinally compared phonemic and semantic fluency performance between 49 dialyzed patients and 30 controls. Overall, patients performed below controls only on the phonemic fluency task. Furthermore, their performance on this task declined over time, whereas there was no change in semantic fluency. Moreover, this decline was related to the presence of hypertension and higher blood urea nitrogen. We suggest that these findings may be due to a combination of vascular and topic effects that impact more on fronto-subcortical than temporal lobe networks, but this speculation requires direct confirmation.

Formation of Blood Foam in the Air Trap During Hemodialysis Due to Insufficient Automatic Priming of Dialyzers.

PubMed

Jonsson, Per; Lindmark, Lorentz; Axelsson, Jan; Karlsson, Lars; Lundberg, Lennart; Stegmayr, Bernd

2018-05-01

We were encouraged to investigate the reasons for large amounts of foam observed in bloodlines during hemodialysis (HD). Foam was visible in the venous air trap within the Artis Gambro dialysis device. Estimates of the extent of foam were graded (0-no foam, 10-extensive foam) by two persons that were blind to the type of dialyzer used. Thirty-seven patients were involved in the dialysis procedures. Consecutive dialyses were graded using dialyzers from Fresenius Medical Care (CorDiax dialyzers that were used for high flux HD-FX80 and FX100, and for hemodiafiltration-FX1000). The extracorporeal circuit was primed automatically by dialysate using Gambro Artis software 8.15 006 (Gambro, Dasco, Medolla Italy, Baxter, Chicago, IL, USA). The priming volume recommended by the manufacturer was 1100 mL, whereas our center uses 1500 mL. Extensive amounts of blood foam were visual in the air traps. Although the manufacturer recommended extension of priming volume up to 3000 mL, this did not eliminate the foam. Microbubble measurement during HD revealed the air to derive from the dialyzers. When changing to PF210H dialyzers (Baxter) and using a priming volume of 1500 mL, the foam was significantly less (P < 0.01). The extent of foam correlated with the size of the FX-dialyzer surface (P = 0.002). The auto-priming program was updated to version 8.21 by the manufacturer and the extent of foam in the air trap using FX dialyzers was now reduced and there was no longer a difference between FX and PF dialyzers, although less foam was still visible in the venous air trap during several dialyses. In conclusion, this study urgently calls attention to blood foam development in the venous air trap when using Artis devices and priming software 8.15 in combination with Fresenius dialyzers. Updated auto-priming software (version 8.21) of Artis should be requested to reduce the extent of foam for the Fresenius dialyzers. Other interactions may also be present. We recommend further studies to clarify these problems. Meanwhile caution is warranted for the combined use of dialysis devices and dialyzers with incompatible automatic priming. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

β-Blocker Dialyzability and Mortality in Older Patients Receiving Hemodialysis

PubMed Central

Dixon, Stephanie N.; Fleet, Jamie L.; Roberts, Matthew A.; Hackam, Daniel G.; Oliver, Matthew J.; Suri, Rita S.; Quinn, Robert R.; Ozair, Sundus; Beyea, Michael M.; Kitchlu, Abhijat; Garg, Amit X.

2015-01-01

Some β-blockers are efficiently removed from the circulation by hemodialysis (“high dialyzability”) whereas others are not (“low dialyzability”). This characteristic may influence the effectiveness of the β-blockers among patients receiving long-term hemodialysis. To determine whether new use of a high-dialyzability β-blocker compared with a low-dialyzability β-blocker associates with a higher rate of mortality in patients older than age 66 years receiving long-term hemodialysis, we conducted a propensity-matched population-based retrospective cohort study using the linked healthcare databases of Ontario, Canada. The high-dialyzability group (n=3294) included patients initiating atenolol, acebutolol, or metoprolol. The low-dialyzability group (n=3294) included patients initiating bisoprolol or propranolol. Initiation of a high- versus low-dialyzability β-blocker was associated with a higher risk of death in the following 180 days (relative risk, 1.4; 95% confidence interval, 1.1 to 1.8; P<0.01). Supporting this finding, we repeated the primary analysis in a cohort of patients not receiving hemodialysis and found no significant association between dialyzability and the risk of death (relative risk, 1.0; 95% confidence interval, 0.9 to 1.3; P=0.71). β-Blocker exposure was not randomly allocated in this study, so a causal relationship between dialyzability and mortality cannot be determined. However, our findings should raise awareness of this potentially important drug characteristic and prompt further study. PMID:25359874

Large volume continuous counterflow dialyzer has high efficiency

NASA Technical Reports Server (NTRS)

Mandeles, S.; Woods, E. C.

1967-01-01

Dialyzer separates macromolecules from small molecules in large volumes of solution. It takes advantage of the high area/volume ratio in commercially available 1/4-inch dialysis tubing and maintains a high concentration gradient at the dialyzing surface by counterflow.

Extended reuse of polysulfone hemodialysis membranes using citric acid and heat.

PubMed

Tonelli, Marcello; Dymond, Clayton; Gourishankar, Sita; Jindal, Kailash K

2004-01-01

The concomitant use of citric acid and prolonged exposure to heat (CAH) is an increasingly common alternative to purely chemical means of reusing dialyzers. However, there are no data on the effects of reprocessing dialyzers with CAH beyond 15 uses. Increasing the number of reuses with CAH cannot be systematically undertaken unless its safety is documented. We hypothesized that discarding polysulfone dialyzers after the 25th rather than the 15th use would result in increased clearance of beta2-microglobulin (beta2MG) without clinically significant changes in small solute clearance or albumin loss. We studied 15 Fresenius F80B polysulfone dialyzers in five chronic hemodialysis patients. Dialyzers were reprocessed using 1.5% citric acid solution heated to 95 degrees C. Representative fractional collection and 10 minute timed collections of dialysate were performed at baseline and during uses 5, 10, 15, 20, and 25 for each dialyzer. Dialysate-side urea, creatinine, and beta2MG clearances were calculated, and total albumin was measured in dialysate. We used a mixed model to adjust for repeated measures (both within a given dialyzer and for the multiple dialyzers per patient). Of the 15 dialyzers studied, 3 (20%) failed before the 25th use. There was no significant change in urea or creatinine clearance with additional reuse (overall p values 0.20 and 0.60, respectively). A sustained increase in beta2MG clearance was observed after the fifth treatment compared with the first use (p < 0.001). Fractional collection showed that dialysate albumin loss increased significantly with additional reuses (p < 0.001) but did not increase significantly above baseline until treatment 25. Reprocessing of polysulfone dialyzers with CAH 25 times significantly increased albumin loss and beta2MG clearance but did not appear to affect urea or creatinine clearance. Increasing the maximum number of uses to 20 may permit cost savings compared with current practice without additional risk.

Clinical study of heparin-free hemodialysis with the inside of hollow fibers in dialyzer coated by human albumins.

PubMed

Wu, Xixin; Chen, Huaji

2002-12-01

To investigate the therapeutics of heparin-free hemodialysis (HD) with the inside of hollow fibers in a dialyzer coated with human albumins (HFHd-A1). Clinical contrast study between HFHd-A1 and heparin-free HD with hollow fibers in dialyzer by normal saline flush (HFHd-NS) was performed by adopting the cross-over design method. The dialysis effect, the effect on life signs, blood platelet functions, change of dialyzer fiber-bundle volume, appearance image, and image of scanning electron microscopy of the inside of hollow fibers in dialyzer after dialysis and the biocompatibility of dialyzer of two HD methods were compared. HFHd-A1 could overcome all shortcomings of HFHd-NS and had more merits and increased expenses for HFHd-A1 were not high. HFHd-A1 was an effective and feasible method which could salvage patients with bleeding diseases or bleeding tendency and who need HD. Copyright 2002 S. Karger AG, Basel

Milk peptides increase iron dialyzability in water but do not affect DMT-1 expression in Caco-2 cells.

PubMed

Argyri, Konstantina; Tako, Elad; Miller, Dennis D; Glahn, Raymond P; Komaitis, Michael; Kapsokefalou, Maria

2009-02-25

In vitro digestion of milk produces peptide fractions that enhance iron uptake by Caco-2 cells. The objectives of this study were to investigate whether these fractions (a) exert their effect by increasing relative gene expression of DMT-1 in Caco-2 cells and (b) enhance iron dialyzability when added in meals. Two milk peptide fractions that solubilize iron were isolated by Sephadex G-25 gel filtration of a milk digest. These peptide fractions did not affect relative gene expression of DMT-1 when incubated with Caco-2 cells for 2 or 48 h. Dialyzability was measured after in vitro simulated gastric and pancreatic digestion. Both peptide fractions enhanced the dialyzability of iron from ferric chloride added to PIPES buffer, but had no effect on dialyzability from milk or a vegetable or fruit meal after in vitro simulated gastric and pancreatic digestion. However, dialyzability from milk was enhanced by the addition of a more concentrated lyophilized peptide fraction.

Monocyte production of transforming growth factor beta in long-term hemodialysis: modulation by hemodialysis membranes.

PubMed

Mege, J L; Capo, C; Purgus, R; Olmer, M

1996-09-01

Cytokines are likely involved in hemodialysis-associated complications such as immunodeficiency and beta 2 microglobulin amyloidosis. Because transforming growth factors beta (TGF beta) exert immunosuppressive effects on lymphocytes, down-modulate monocyte functions, and promote fibrosis, we hypothesize that they participate in the deleterious effects of hemodialysis. We investigated the production of TGF beta 1 and TGF beta 2 by monocytes from controls and patients dialyzed with high-flux cellulose triacetate (CT) and polyacrylonitrile (PAN) membranes. The detection of both TGF beta s required an acidification step, suggesting that they are secreted as latent complexes. The spontaneous production of TGF beta 1 and TGF beta 2 was significantly higher in patients dialyzed with CT or PAN than in controls, but the oversecretion of TGF beta 1 was more sustained in CT-treated patients than in PAN-dialyzed patients. The production of interleukin-6 (IL-6) was increased in both patient groups as compared with controls. In contrast to TGF beta 1, the increase was greater in PAN-treated patients than in CT-treated patients, and the release of tumor necrosis factor alpha (TNF alpha) was increased only in PAN-treated patients. Taken together, our results show that hemodialysis is associated with the oversecretion of monocyte cytokines. Moreover, the type of dialysis membrane specifically affects the balance between the secretion of suppressive cytokines such as TGF beta and that of inflammatory cytokines such as IL-6 and TNF alpha.

Prospective crossover trial of the influence of vitamin E-coated dialyzer membranes on T-cell activation and cytokine induction.

PubMed

Girndt, M; Lengler, S; Kaul, H; Sester, U; Sester, M; Köhler, H

2000-01-01

Cytokine induction by dialyzer membranes has been related to several acute and chronic side effects of hemodialysis treatment, among them being immune dysfunction and progressive atherosclerosis. Surface modification of cuprophane dialyzers with the antioxidant vitamin E is a new approach to enhance biocompatibility and improve cytokine levels, as well as immune function. Twenty-one patients undergoing treatment with hemophane (HE) dialyzers were enrolled onto a crossover study with a vitamin E-coated (VE) dialyzer or a synthetic polyamide (PA) dialyzer. In vitro assays of lymphocyte activation and measurements of cytokine induction were performed to evaluate biocompatibility. Four weeks of treatment with either VE or PA dialyzers enhanced in vitro proliferation of peripheral blood leukocytes in comparison to treatment with HE membranes used before study entry. Enhancement of lymphocyte function was independent of dialysis efficiency, which was kept constant during the study. In the interdialytic interval, preactivation of monocytes for the production of interleukin-6 (IL-6) did not differ between VE or PA dialysis. In contrast, the VE membrane reduced acute production of IL-6 during a dialysis treatment, whereas the PA membrane did not. Unlike IL-6, the regulatory cytokine IL-10 is not inhibited by either membrane. This is important because IL-10 is believed to have a beneficial effect on immune function in dialysis patients. The VE membrane, despite being based on a cuprophane backbone, is similar to the highly biocompatible PA dialyzer in terms of its effect on lymphocyte function, whereas it exerts an additional suppressive effect on the overproduction of proinflammatory cytokines.

Dialyzer best practice: single use or reuse?

PubMed

Lacson, Eduardo; Lazarus, J Michael

2006-01-01

Outcome studies have shown either no additional risk or a small additional risk for hospitalization and mortality associated with reprocessing dialyzers. Although the risks from reprocessing dialyzers have yet to be fully elucidated, reuse can be done safely if it is performed in full compliance with the standards of Association for the Advancement of Medical Instrumentation (AAMI). Like most industrial processes, however, complete control of the reuse process in a clinical environment and full compliance with regulations at all times is difficult. Potential errors and breakdowns in the reuse process are continuing concerns. The quality controls for reprocessing of dialyzers are not equal to the rigor of the manufacturing process under the purview of the U.S. Food and Drug Administration (FDA). Therefore, if one were to determine "best practice," single use is preferable to reuse of dialyzers based on medical criteria and risk assessment. The long-term and cumulative effects of exposure to reuse reagents are unknown and there is no compelling medical indication for reprocessing of dialyzers. The major impediment when deciding to convert from reuse to single use of dialyzers is economic. The experience in Fresenius Medical Care-North America (FMCNA) facilities demonstrates that converting from a practice of reuse to single use is achievable. However, the overall economic impact of conversion to single use is provider specific. The dominance of reuse has been negated of late by a major shift in practice toward single use. Physicians and patients should be well informed in making decisions regarding the practice of single use versus reuse of dialyzers.

Expression of beta2-microglobulin and c-fos mRNA: is there an influence of high- or low-flux dialyzer membranes?

PubMed

Haufe, C C; Eismann, U; Deppisch, R M; Stein, G

2001-02-01

Dialysis-related amyloidosis is an important complication of long-term hemodialysis (HD) therapy with several pathogenetic factors. One of them is the influence of the dialyzer membrane type on the synthesis of beta2-microglobulin (beta2m). In vitro results are controversial. Thus, the hypothesis of whether in vivo beta2m generation is induced by the HD procedure and whether this induction depends on the type of the used dialyzer membrane should be tested. The aim of the present study was to investigate the influence of "biocompatible" high-flux versus "bioincompatible" low-flux HD on in vivo beta2m generation as well as the induction of the early activation gene c-fos in peripheral blood cells. Six nondiabetic HD patients [mean age 46 (21 to 69) years; Kt/V> 1.2] were included in a randomized crossover study using either a low-flux (cellulosic/cuprophan) or a high-flux (polyamide) dialyzer membrane. At the end of a four-week run-in period for each membrane, whole blood samples were taken before, immediately at, and four hours after the end of the dialysis session. MRNA was extracted, and after transcription to cDNA, quantitative polymerase chain reaction was performed for the beta2m gene, the early response gene c-fos, and the GAP-DH housekeeping gene. Based on the applied method for detection of specific mRNA, the results were given as ratio of beta2m or c-fos cDNA per GAP-DH cDNA. General cell activation during HD was indicated by increasing mRNA expression of c-fos related to the time course of the dialysis session, whereas beta2m did not change significantly. However, no difference was found when comparing the low-flux and the high-flux dialyzer membranes. Despite the evidence for activation of peripheral blood cells, as indicated by increasing c-fos message, no sign of beta2m mRNA induction during HD procedure with different dialyzer membranes was seen. Our results suggest that there is post-transcriptional regulation of beta2m generation and/or release as well as the influence of the dialyzer membrane type on post-translational processes, that is, advance glycation end products (AGE) or conformational modification of the beta2m protein. Furthermore, our data demonstrate that gene expression patterns during dialysis and/or uremia are not homogenous and need to be investigated further, especially with respect to the proinflammatory role of early leukocyte activation signals.

The sugar model: catalytic flow reactor dynamics of pyruvaldehyde synthesis from triose catalyzed by poly-l-lysine contained in a dialyzer

NASA Technical Reports Server (NTRS)

Weber, A. L.

2001-01-01

The formation of pyruvaldehyde from triose sugars was catalyzed by poly-l-lysine contained in a small dialyzer with a 100 molecular weight cut off (100 MWCO) suspended in a much larger triose substrate reservoir at pH 5.5 and 40 degrees C. The polylysine confined in the dialyzer functioned as a catalytic flow reactor that constantly brought in triose from the substrate reservoir by diffusion to offset the drop in triose concentration within the reactor caused by its conversion to pyruvaldehyde. The catalytic polylysine solution (400 mM, 0.35 mL) within the dialyzer generated pyruvaldehyde with a synthetic intensity (rate/volume) that was 3400 times greater than that of the triose substrate solution (12 mM, 120 mL) outside the dialyzer. Under the given conditions the final yield of pyruvaldehyde was greater than twice the weight of the polylysine catalyst. During the reaction the polylysine catalyst was poisoned presumably by reaction of its amino groups with aldehyde reactants and products. Similar results were obtained using a dialyzer with a 500 MWCO. The dialyzer method of catalyst containment was selected because it provides a simple and easily manipulated experimental system for studying the dynamics and evolutionary development of confined autocatalytic processes related to the origin of life under anaerobic conditions.

Impact of blood and dialysate flow and surface on performance of new polysulfone hemodialysis dialyzers.

PubMed

Mandolfo, S; Malberti, F; Imbasciati, E; Cogliati, P; Gauly, A

2003-02-01

Optimization of hemodialysis treatment parameters and the characteristics of the dialyzer are crucial for short- and long-term outcome of end stage renal disease patients. The new high-flux membrane Helixone in the dialyzer of the FX series (Fresenius Medical Care, Germany) has interesting features, such as the relationship of membrane thickness and capillary diameter which increases middle molecule elimination by convection, as well as higher capillary packing and microondulation to improve the dialysate flow and distribution. Blood flow, dialysate flow and surface area are the main determinants of the performance of a dialyzer, however the impact of each parameter on small and middle molecule clearance in high flux dialysis has not been well explored. In order to find the best treatment condition for the new dialyzer series, we evaluated urea, creatinine, phosphate clearances and reduction rate of beta2-microglobulin in ten stable patients treated with different blood flows (effective Qb 280 and 360 ml/min), dialysate flow (Qd 300 or 500 ml/min) and dialyzer surfaces (1.4 and 2.2 m2, FX60 or FX100). KoA and Kt/V were also calculated. Blood flow, dialysate flow and surface area demonstrated a significant and independent effect on clearance of urea, creatinine and phosphate, as well as on Kt/V. Small solute clearance was stable over the treatment. In contrast to small solutes, reduction rate of beta2-microglobulin was related to increasing dialyzer surface only. The new dialyzer design of the FX series proves highly effective due to improved dialysate distribution and reduced diffusive resistance as shown by the small solute clearance. A high reduction rate of beta2-microglobulin is favored by improved fiber geometry and pore size distribution. These findings have potential long-term benefits for the patient.

Dialyzer-related Thrombocytopenia due to a Polysulfone Membrane.

PubMed

Kobari, Eri; Terawaki, Hiroyuki; Takahashi, Yasuhito; Kusano, Yuki; Sakurai, Kaoru; Matsunaga, Keiko; Fukushima, Naotaro; Suzuki, Sawako; Tanaka, Ken-Ichi; Hayashi, Yoshimitsu; Watanabe, Tsuyoshi; Nakayama, Masaaki

2016-01-01

A 72-year-old Japanese woman was admitted to our hospital with rapidly progressive glomerulonephritis associated with anti-glomerular basement membrane antibody. Hemodialysis (HD) therapy was initiated on the day of admission using a biocompatible polysulfone (PS) membrane. Her platelet count (PLT; ×10(4)/μL) decreased gradually from 58.7 (day 1) to 5.8 (day 25). Considering the possibility of dialyzer-related thrombocytopenia (DRT), we measured her PLT count before and after the HD session on day 72, which revealed a dramatic decrease of 7.5 to 4.3. This finding suggested that the PS dialyzer caused PLT depletion. After discontinuation of the PS dialyzer, DRT was resolved.

Improved management of intradialytic hypotension (IDH) using vitamin E-bonded polysulfone membrane dialyzer.

PubMed

Matsumura, Masaki; Sasaki, Hisako; Sekizuka, Kumiko; Sano, Hiroyuki; Ogawa, Kouji; Shimizu, Chihiro; Yoshida, Hiroaki; Kobayashi, Satsuki; Koremoto, Masahide; Aritomi, Masaharu; Ueki, Kazue

2010-03-01

Intradialytic hypotension (IDH) is a common clinical trait in hemodialysis (HD) which is caused by poor biocompatibility of the dialyzer membrane. Aiming to improve IDH, vitamin E-bonded polysulfone dialyzer (VPS-H) was evaluated in a pilot study. Eight IDH patients on standard HD were switched from their conventional high-flux dialyzers to VPS-H, and intradialytic blood pressure (BP) was monitored regularly for 10 months. The results showed that hypotension of systolic BP (SBP), diastolic BP (DBP) and pulse pressure (PP) during the session were improved after changing the dialyzer. Notably, almost all the values recorded from 120 minutes into the session until the end of the treatment in the period between the second and tenth month after treatment were significantly different from the corresponding baseline values. Moreover, after 8 to 10 months, the SBP prior to a dialysis session was significantly reduced compared with baseline values. On the other hand, the pulse rate showed no difference throughout the study period. This study provides early evidence of the beneficial role that vitamin E-bonded dialyzers may have in preventing IDH. Larger controlled trials are needed to confirm this original finding.

The cell engineering construction and function evaluation of multi-layer biochip dialyzer.

PubMed

Zhu, Wen; Li, Jiwei; Liu, Jianfeng

2013-10-01

We report the fabrication and function evaluation of multi-layer biochip dialyzer. Such device may potentially be applied to the wearable hemodialysis systems. By merging the advantages of microfluidic chip technology with cell engineering, both functions of glomerular filtration and renal tubule physiological activity are integrated in the same device. This device is designed into a laminated structure, in which the chip number of the superimposed layer can be arbitrarily tailored in accordance with the requirements of dialysis capacity. We propose that such structure can overcome the obstacles of large size and detached structure of the traditional hollow fiber dialyzer. To construct this multilayer biochips dialyzer, two types of dialyzer device with two-layered and six-layered chips are assembled, respectively. Cell adhesion and proliferation on three different dialysis membrane materials under static and dynamic conditions are investigated and compared. The filtration capability, re-absorption function and excrete ammonia function of the resulting multi-layer biochip dialyzer are evaluated. The results reveal that the constructed device can perform higher filtration efficiency and also play a role of renal tubule. This methodology may be useful in developing "scaling down" artificial kidneys that can act as wearable or even implantable hemodialysis systems.

Design Concept of Dialyzer Biomaterials: How to Find Biocompatible Polymers Based on the Biointerfacial Water Structure.

PubMed

Tanaka, Masaru

2017-01-01

Although various types of materials have been used widely in dialyzers, most biomaterials lack the desired functional properties to interface with blood and have not been engineered for optimum performance. Therefore, there is increasing demand to develop novel materials to address such problems in the dialysis arena. Numerous parameters of polymeric biomaterials can affect biocompatibility in a controlled manner. The mechanisms responsible for the biocompatibility of polymers at the molecular level have not been clearly demonstrated, although many theoretical and experimental efforts have been made to try and understand them. Moreover, water interactions have been recognized as fundamental for the blood response to contact with polymers. We have proposed the 'intermediate water' concept and hypothesized that intermediate water, which prevents the proteins and blood cells from directly contacting the polymer surface, or nonfreezing water on the polymer surface, plays an important role in the biocompatibility of polymers. This chapter provides an overview of the recent experimental progress of biocompatible polymers measured by thermal, spectroscopic, and surface force techniques. Additionally, it highlights recent developments in the use of biocompatible polymeric biomaterials for dialyzers and provides an overview of the progress made in the design of multifunctional biomedical polymers by controlling the biointerfacial water structure through precision polymer synthesis. Key Messages: Intermediate water was found only in hydrated biopolymers (proteins, polysaccharides, and nucleic acids, DNA and RNA) and hydrated biocompatible synthetic polymers. Intermediate water could be one of the main screening factors for the design of appropriate dialyzer materials. © 2017 S. Karger AG, Basel.

Enhancement of the blood compatibility of dialyzer membranes by the physical adsorption of human thrombomodulin (ART-123).

PubMed

Omichi, Masaaki; Matsusaki, Michiya; Kato, Shinya; Maruyama, Ikuro; Akashi, Mitsuru

2010-11-01

ART-123 is a recombinant soluble human thrombomodulin (hTM) with excellent anticoagulant activity. We focused on improving the blood compatibility of the polysulfone-polyvinylpyrrolidone dialyzer surface by the physical adsorption of ART-123 onto the surface. The blood compatibility of the dialyzer with the hTM adsorbed membrane was evaluated by measuring the differential pressure between the arterial and the venous pressures and by blood parameters during blood circulation. The hTM adsorbed dialyzer membrane inhibited blood clot formation without heparin administration due to the anticoagulant activity of hTM for over 4 h. The physically adsorbed hTM was stable during blood circulation, and it did not affect activated clotting time, which is significant drawback of heparin administration, and blood cell counts of RBC, WBC, or platelets. The physical adsorption of hTM onto the dialyzer membrane will be a simple and safe method to prevent blood coagulation during dialysis instead of heparin administration. © 2010 Wiley Periodicals, Inc.

Impact of dialyzer membrane on apoptosis and function of polymorphonuclear cells and cytokine synthesis by peripheral blood mononuclear cells in hemodialysis patients.

PubMed

Andreoli, Maria C C; Dalboni, Maria A; Watanabe, Renato; Manfredi, Silvia R; Canziani, Maria E F; Kallás, Esper G; Sesso, Ricardo C; Draibe, Sergio A; Balakrishnan, Vaidyanathapuram S; Jaber, Bertrand L; Liangos, Orfeas; Cendoroglo, Miguel

2007-12-01

In an in vivo crossover trial, we compared a cellulosic with a synthetic dialyzer with respect to polymorphonuclear cells (PMN) function and apoptosis, cytokine serum levels and synthesis by peripheral blood mononuclear cells (PBMC), and complement activation. Twenty hemodialysis (HD) patients were assigned in alternate order to HD with cellulose acetate (CA) or polysulfone (PS) dialyzer. After 2 weeks, patients were crossed over to the second dialyzer and treated for another 2 weeks. Apoptosis was assessed by flow cytometry in freshly isolated PMN. Phagocytosis and production of peroxide by PMN were studied by flow cytometry in whole blood. PBMC were isolated from blood samples and incubated for 24 h with or without lipopolysaccharide (LPS). There was no impact of dialyzer biocompatibility on PMN apoptosis and function, cytokine synthesis by PBMC or on their serum levels, serum levels of C3a, and terminal complement complex (TCC). Nevertheless, after HD, serum levels of complement correlated negatively with PMN phagocytosis and peroxide production, and positively with PMN apoptosis and cytokine production by PBMC. Although the results did not show a dialyzer advantage on the immunologic parameters, complement activation may have modulated cell function and apoptosis after HD.

Bioincompatibility of dialyzer membranes may have a negative impact on outcome of acute renal failure, independent of the dose of dialysis delivered: a retrospective multicenter analysis.

PubMed

Schiffl, H; Lang, S M; Haider, M

1998-01-01

The mortality rate of critically ill patients with acute renal failure (ARF) has remained high. The impact of vigorous intermittent hemodialysis (IHD) on the outcome of ARF has not been validated. In this retrospective multicenter analysis, 154 patients with ARF were treated daily (intensive) or on alternate days (conventional) using complement and cell activating cuprophane (bioincompatible) or high-flux polysulfone dialyzer membranes with insignificant effects on circulating complement or cells (biocompatible). At initiation of IHD, all four groups were similar in patient characteristics and ARF factors. The use of synthetic membranes resulted in a reduced mortality rate (18% vs 45%; p < 0.001) and shorter duration of ARF (8 vs 15 sessions; p < 0.001). Daily IHD with cellulose based membranes tended to increase mortality rates compared with conventional cuprophane dialysis (37% vs 53%). Intensive IHD with polysulfone membranes resulted in a further decrease in overall mortality rates (15% vs 22%). This retrospective analysis shows that bioincompatibility of dialyzer membranes may be more important for the outcome of patients with ARF than the dose of dialysis. Its impact on outcome occurs independently of the dose of dialysis delivered.

Effects of vitamin E-coated dialysis membranes on anemia, nutrition and dyslipidemia status in hemodialysis patients: a meta-analysis.

PubMed

Huang, Jing; Yi, Bin; Li, Ai-Mei; Zhang, Hao

2015-04-01

This was controversial whether vitamin E-coated dialyzer therapy was beneficial for the complications associated with hemodialysis. Therefore, we performed this systematic review to evaluate the effects of vitamin E-coated dialyzer. Related trials were searched from multiple electronic databases. We conducted meta-analysis to assess changes in the predefined outcomes using RevMan 5.3 software. Meta-analysis showed vitamin E-coated dialyzer therapy could decrease erythropoietin (EPO) resistance index (SMD, -0.24; 95% CI, -0.47 to -0.01; p = 0.04). However, pooled-analysis showed vitamin E-coated dialyzer therapy could not decrease weekly EPO dose (SMD, -0.11; 95% CI, -0.32 to 0.09; p = 0.28) and intima-media thickness (IMT) of the carotid artery (MD, -0.09; 95% CI, -0.2 to 0.01; p = 0.09), and vitamin E-coated dialyzer therapy did not improve the serum hemoglobin (MD, -0.03; 95% CI, -0.18 to 0.13; p = 0.74), albumin levels (SMD, -0.64; 95% CI, -1.62 to 0.34; p = 0.2), in addition, there was no significant difference in serum cholesterol (SMD, -0.07; 95% CI, -0.45 to 0.31; p = 0.71), triglycerides (MD, -2.77; 95% CI, -32.42 to 26.87; p = 0.85), high density lipoprotein (HDL) (SMD, 0.24; 95% CI, -0.14 to 0.62; p = 0.22) and low density lipoprotein (LDL) (SMD, 0.00; 95% CI, -0.38 to 0.37; p = 0.98) levels. Vitamin E-coated dialyzer may reduce the EPO resistance, but there is no conclusive evidence that vitamin E-coated dialyzer can improve the renal anemia, malnutrition, dyslipidemia and atherosclerosis status in hemodialysis (HD) patients. However, high-quality trials with hard clinical endpoints are required to fully elucidate the clinical value of vitamin E-coated dialyzer therapy.

Albumin dialysis in cirrhosis with superimposed acute liver injury: a prospective, controlled study.

PubMed

Heemann, Uwe; Treichel, Ulrich; Loock, Jan; Philipp, Thomas; Gerken, Guido; Malago, Massimo; Klammt, Sebastian; Loehr, Matthias; Liebe, Stephan; Mitzner, Steffen; Schmidt, Reinhardt; Stange, Jan

2002-10-01

Patients with liver cirrhosis and a superimposed acute injury with progressive hyperbilirubinemia have a high mortality. A prospective, controlled study was performed to test whether hyperbilirubinemia, 30-day survival, and encephalopathy would be improved by extracorporeal albumin dialysis (ECAD). Twenty-four patients were studied; 23 patients had cirrhosis; 1 had a prolonged cholestatic drug reaction and was excluded from per protocol (PP) analysis. Patients had a plasma bilirubin greater than 20 mg/dL and had not responded to prior standard medical therapy (SMT). Patients were randomized to receive SMT with ECAD or without (control). ECAD was performed with an extracorporeal device that dialyzes blood in a hollow fiber dialyzer (MW cutoff < 60 kd) against 15% albumin. Albumin-bound molecules transfer to dialysate albumin that is regenerated continuously by passage through a charcoal and anion exchange column and a conventional dialyzer. ECAD was associated with improved 30-day survival (PP, 11 of 12 ECAD, 6 of 11 controls; log rank P <.05). Plasma bile acids and bilirubin decreased on average by 43% and 29%, respectively, in the ECAD group after 1 week of treatment, but not in the control group. Renal dysfunction and hepatic encephalopathy improved in the ECAD group, but worsened significantly in the control group. ECAD was safe, with adverse events being rare and identical in both groups. In conclusion, ECAD appears to be effective and safe for the short-term treatment of patients with cirrhosis and superimposed acute injury associated with progressive hyperbilirubinemia and may be useful for increasing survival in such patients awaiting liver transplantation.

Surface characterization of dialyzer polymer membranes by imaging ToF-SIMS and quantitative XPS line scans.

PubMed

Holzweber, Markus; Lippitz, Andreas; Krueger, Katharina; Jankowski, Joachim; Unger, Wolfgang E S

2015-03-24

The surfaces of polymeric dialyzer membranes consisting of polysulfone and polyvinylpyrrolidone were investigated regarding the lateral distribution and quantitative surface composition using time-of-flight secondary-ion-mass-spectrometry and x-ray photoelectron spectroscopy. Knowledge of the distribution and composition on the outer surface region is of utmost importance for understanding the biocompatibility of such dialyzer membranes. Both flat membranes and hollow fiber membranes were studied.

The effect of hemodialysis and dialyzer biocompatibility on erythrocyte glutathione-defense system in chronic hemodialysis patients.

PubMed

Alhamdani, M S; Al-Najjar, A F; Al-Kassir, A H

2005-06-01

Uremic patients, especially those receiving regular hemodialysis (HD) treatment, are at high risk of oxidative damage by noxious free radicals and reactive oxygen species (ROS). The erythrocyte glutathione-defense system (GSH-DS) is one of the major enzymatic means of scavenging and detoxifying ROS. This study aimed to elucidate the effect of HD and dialyzer biocompatibility on erythrocyte GSH-DS in uremic patients on maintenance HD treatment. Twenty-five healthy volunteers and 42 HD patients were enrolled in this study. Blood samples were drawn immediately before and after HD session, and erythrocyte glutathione (GSH) level as well as the activities of the enzymes glucose-6-phosphate dehydrogenase (G6PD), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-Rd), and glutathione S-transferase (GST) were measured. To evaluate the effect of dialyzer type on the studied parameters the patients were were subdivided into two groups: those who had dialysis with cuprophane (CU) membranes (n=23) and those who received dialysis with the aid of polysulfone (PS) membranes (n=19). The activities of G6PD and GSH-Px as well as GSH level were significantly decreased in HD patients as compared with controls. On the other hand, the activities of GSSG-Rd and GST were significantly elevated among HD patients in comparison with control values. A single HD session, regardless of the type of dialyzer, did not induce any significant effect on any of the measured parameters, although G6PD activity increased significantly after dialysis. CU membrane did not result in any change in GSH or its metabolizing enzymes, while PS dialyzers exerted a minor but significant restoration in GSH-DS. The antioxidant pool, as represented by GSH-DS, is significantly affected by dialyzer type in HD patients being significantly corrected with polysulfone dialyzer.

Surface characterization of dialyzer polymer membranes by imaging ToF-SIMS and quantitative XPS line scans

PubMed Central

Holzweber, Markus; Lippitz, Andreas; Krueger, Katharina; Jankowski, Joachim; Unger, Wolfgang E. S.

2015-01-01

The surfaces of polymeric dialyzer membranes consisting of polysulfone and poly-vinylpyrrolidone were investigated regarding the lateral distribution and quantitative surface composition using time-of-flight secondary-ion-mass-spectrometry and x-ray photoelectron spectroscopy. Knowledge of the distribution and composition on the outer surface region is of utmost importance for understanding the biocompatibility of such dialyzer membranes. Both flat membranes and hollow fiber membranes were studied. PMID:25711334

Is the bioreactivity of vitamin-E-modified dialyzer an expression of increased plasmatic vitamin E concentration?

PubMed

Senatore, Massimimo; Nicoletti, A; Rizzuto, G

2002-10-01

The present study was designed to test the biocompatibility of a new vitamin E-modified multilayer membrane compared with highly biocompatible polysulphone dialyzer and acrylonitrile dialyzer. Thirty patients (mean age 53.2 +/- 15.3 SD years; dialytic age 36 +/- 5.6 months) were selected for the study. The study was divided into three periods of 6 months (phases A, B and C). In the first phase (from Jan. 1999 to June 1999) patients undergoing maintenance bicarbonate dialysis were randomly divided into three filter groups composed, respectively, of 10 patients: acrylonitrile group, polysulphone group and vitamin E-coated dialyzer group. In the phase B (from July 1999 to Dec. 1999) and in the phase C (from Jan. 2000 to June 2000), all three groups changed their own dialysis membranes. Vitamin E-coated dialyzer causes significant decreases in beta(2)-microglobulin, ferritin and immunoglobulin G, a normalization of complement C3 and an increase of plasmatic vitamin E compared to other filters. In the VE group homocysteine decreases but not in a significant manner. In addition, this dialyzer seems not to influence lipid pattern and protein-energy malnutrition parameters. These results clearly show a positive effect of this new filter in influencing different biochemical parameters, perhaps saving vitamin E and reducing polymorphonuclear cell activation. Copyright 2002 S. Karger AG, Basel

[Does a short-term hemodialysis treatment influence function of the pituitary-testicular axis in patients with chronic renal failure?].

PubMed

Starzyk, J; Grzeszczak, W

1993-01-01

Abnormal function of the pituitary-gonadal axis is a well documented endocrine abnormality in chronic renal failure (CRF). The purpose of the work was to assess the influence of the short-term haemodialysis treatment on LH, FSH and testosterone secretion. In 17 men dialyzed up to 50 months and 10 non-dialyzed male patients with advanced CRF the test of stimulation with LHRH was done. Results obtained in patients were compared with those assessed in healthy subjects. Significantly higher concentration of LH and FSH and lower concentration of testosterone in serum under basal conditions were found in patients as compared to controls. Basal concentrations of LH, FSH and testosterone in dialyzed patients and in non dialyzed men were similar. The area under the curve of LH, FSH and testosterone in both groups of patients was similar. These results suggest that in men dialyzed shorter than 50 months haemodialysis treatment does not change significantly the function of the pituitary-testicular axis as compared to men with advanced CRF.

The study of IL-1 beta, TNF-alpha, IL-6 gene expression and plasma levels on hemodialysis before and after dialyzer reuse.

PubMed

Qian, J; Yu, Z; Dai, H; Huang, P; Zhang, Q; Cheng, F; Chen, S

1997-07-01

To investigate the biocompatibility of dialyzer reuse. Twenty-two hemodialysis patients were randomized into cuprophan (CU, 7), polymethylmethacrylate (PMMA, 7) and polysulphone (PS, 8) membrane groups to observe IL-1 beta, TNF-alpha, IL-6 gene expression and their plasma levels by using themselves as control with enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. Plasma levels of interlukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) were 14.07 +/- 3.32 pg/ml, 67.41 +/- 19.79 pg/ml, 83.67 +/- 40.34 pg/ml; 12.80 +/- 3.01 pg/ml, 49.65 +/- 9.75 pg/ml, 33.36 +/- 12.14 pg/ml and 14.41 +/- 3.16 pg/ml, 80.56 +/- 23.22 pg/ml, 48.14 +/- 16.01 pg/ml, respectively, after patients dialyzed with CU, PMMA and PS membranes. Plasma cytokine levels decreased after reuse compared with those before reuse in each group. But no significant difference was found between them (P > 0.05); the levels of IL-1 beta, TNF-alpha, IL-6 gene expression after reuse were 5.61 +/- 0.33, 2.11 +/- 0.12, 5.04 +/- 0.19%; 2.43 +/- 0.19, 1.29 +/- 0.11, 3.48 +/- 0.20% and 2.48 +/- 0.20, 1.24 +/- 0.11, 3.22 +/- 0.20% respectively by in situ hybridization, and 0.92 +/- 0.07, 0.63 +/- 0.05, 0.53 +/- 0.05; 0.61 +/- 0.06, 0.47 +/- 0.04, 0.37 +/- 0.03 and 0.59 +/- 0.05, 0.44 +/- 0.04, 0.38 +/- 0.03 by RT-PCR, respectively. After reuse there was significant decrease as compared with that before reuse (P < 0.001, P < 0.005 and P < 0.05, respectively). This suggested reprocessing dialyzer with formaldehyde reduced cytokine release and gene expression in peripheral blood mononuclear cells and enhanced dialyzer biocompatibility. It would be beneficial to reduce the dialysis cost and may reduce the complication related to a long term hemodialysis.

Differences in the permeability of high-flux dialyzer membranes for bacterial pyrogens.

PubMed

Schindler, R; Christ-Kohlrausch, F; Frei, U; Shaldon, S

2003-06-01

The increasing use of high-flux membranes for hemodialysis has raised concerns that patients dialyzed with these membranes may be at higher risk of being exposed to cytokine-inducing bacterial substances in the dialysate than patients dialyzed with low-flux membranes. We investigated the permeability of various high-flux membranes for both purified E. coli lipopolysaccharide (LPS) as well as for LPS derived from Stenotrophomonas (Sten.) maltophilia. An in vitro dialysis circuit with saline in the blood compartment of 3 dialyzers containing different membranes (polysulfone, helixone and Diapes) was employed. The dialysate was challenged with increasing doses of sterile filtrates derived from Sten. maltophilia cultures or with purified LPS from E. coli. Samples from the blood compartment were tested for cytokine induction (IL-1beta, IL-6 and TNF) in mononuclear cells as well as for LPS by limulus amebocyte lysate test (LAL). IL-6 induction above sterile controls (< 0.02 ng/ml IL-6) was observed by samples from the blood side of DIAPES dialyzers (1.2 +/- 0.7 ng/ml IL-6) after challenging the dialysate with 4.1 +/- 3.6 U/ml E. coli LPS (9.9 +/- 4.5 ng/ml IL-6). In contrast, at the same challenge dose no significant IL-6 induction above sterile controls was observed by blood side samples of polysulfone (0.15 +/- 0.07 ng/ml) and helixone (0.09 +/- 0.05 ng/ml) dialyzers. Increasing the amount of E. coli LPS in the dialysate further augmented IL-6 induction by blood side samples of Diapes but not of polysulfone and helixone dialyzers. Similar results were obtained for IL-1beta and TNF. After challenging the dialysate with E. coli LPS as well as with cultures of Sten. maltophilia, significantly more LAL reactivity was observed in the blood compartment of Diapes compared to polysulfone and helixone. There are considerable differences between high-flux membranes regarding their permeability for cytokine-inducing substances from E. coli as well as for LPS derived from E. coli and Sten. maltophilia. Dialyzers that leak CIS under aqueous conditions in vivo should not be used unless the dialysate has passed through an ultrafilter.

Impact of using two dialyzers in parallel on phosphate clearance in hemodialysis patients: a randomized trial.

PubMed

Thompson, Stephanie; Manns, Braden; Lloyd, Anita; Hemmelgarn, Brenda; MacRae, Jennifer; Klarenbach, Scott; Unsworth, Larry; Courtney, Mark; Tonelli, Marcello

2017-05-01

Dietary restriction and phosphate binders are the main interventions used to manage hyperphosphatemia in people on hemodialysis, but have limited efficacy. Modifying conventional dialysis regimens to enhance phosphate clearance as an alternative approach remains relatively unstudied. This was a 10-week, 2-arm, randomized crossover study. Participants were prevalent dialysis patients ( n = 32) with consecutive serum phosphate levels >1.6 mmol/L and on stable doses of a phosphate binder. Following a 2-week run-in period, participants were randomized to initiate dialysis using two high flux dialyzers in parallel (blood flow ≥350 mL/min, dialysate flow 800 mL/min) or standard dialysis using one high flux dialyzer (blood flow ≥350 mL/min, dialysate flow of 800 mL/min). Each regimen was 3 weeks in duration. After a 2-week washout period, participants received the alternate regimen. The primary outcome was the mean difference in phosphate clearance by dialyzer strategy. Secondary outcomes were phosphate removal and pre-dialysis serum phosphate. Phosphate clearance for the double dialyzer strategy did not differ significantly from the single dialyzer strategy [mean difference 7.5 mL/min (95% confidence interval, 95% CI, -6.1, 21.0), P = 0.28]. There was no difference in total phosphate removal and pre-dialysis phosphate between the double and single dialyzer strategies [total phosphate removal mean difference -0.2 mmol (95% CI -4.1, 3.7), P = 0.93; pre-dialysis mean difference 0.01 mmol/L (95% CI -0.18, 0.21), P = 0.88]. There was no difference in the proportion of participants who experienced at least one episode of intradialytic hypotension (32 versus 47%, P = 0.13). A limitation of the study was frequent protocol deviations in the dialysis prescription. In this study, the use of two dialyzers in parallel did not increase phosphate clearance, phosphate removal or pre-dialysis serum phosphorus when compared with a standard dialysis treatment strategy. Future studies should continue to evaluate novel methods of phosphate removal using conventional hemodialysis. © The Author 2016. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

The influence of cuprophan and polysulfone membranes on dialyzer reusability and intradialytic complications.

PubMed

Kadiri, S; Kehinde, Z; Arije, A; Salako, B L

2001-09-01

The influence of cuprophan and polysulfone membranes on dialyzer reuse and intradialytic complications was examined in patients receiving chronic haemodialysis. Mean uses were 2.7 +/- 1.3 S.D. and 2.2 +/- 1.0 S.D. for cuprophan and polysulfone respectively (P < 0.001). 20.8% and 35.5% of cuprophan and polysulfone dialyzers respectively did not survive first use (X(2) = 17.4, P < 0.001), being unsuitable for further use. The most common number of uses obtainable was 3 for each type. 2.6% of cuprophan but none of the polysulfone dialyzers were usable over 5 times. Hypotension occurred in 12% and 29% of dialyses with cuprophan and polysulfone dialyzers (P < 0.001), and the difference persisted, but the frequency in each membrane group decreased, with reuse (P < 0.001). First use reactions occurred in 9.5% and 3.9% of dialyses with cuprophan and polysulfone respectively (P < 0.001), and the difference was not affected by reuse (P > 0.1), but the frequency decreased in each group (P < 0.001). Clotting of the dialyzer occurred in 2.2% and 1.9% of cases respectively (P > 0.5), diminished with reuse of cuprophan (P < 0.001), but not with polysulfone (P > 0.5). Cuprophan membrane was more reuseable and was associated with fewer episodes of hypotension, while polysulfone was associated with fewer episodes of first use reactions. Rational choice of membranes can be made during haemodialysis.

Effect of dialyzer membranes on beta-2 microglobulin production in Thai hemodialysis patients.

PubMed

Domrongkitchaiporn, S; Chuncharunee, S; Archararit, N; Atamasirikul, K; Vanichakarn, S

1997-09-01

Responses to different types of dialyzer membranes in an Asian population may differ from those of a Caucasian population. Comparative studies on the effects of different dialyzer membranes on beta-2 microglobulin production are also limited. Therefore, we conducted this study to determine the effects of different dialyzer membranes on in vitro mononuclear cell production of beta-2 microglobulin in 9 Thai hemodialysis patients. Each patient was dialysed with 4 different types of dialyzer, including cuprophane (CUP), cellulose diacetate (CD), polysulphone (PS), and polyacrylonitrile membrane (PAN), each for a 1-month period in a randomized sequence. Mononuclear cell culture was done by taking an immediate post-dialysis blood sample at the end of the 1-month period. Beta-2 microglobulin production from cell culture was determined 24 hours later. Mononuclear cell culture and determination of beta-2 microglobulin production from the culture were also done in 10 normal controls and 10 predialysis ESRD patients. The beta-2 microglobulin productions (microgram/L) were shown as follows; Control CUP CD PS PAN [table: see text] (*p < 0.05 compared to cuprophane membrane). polysulphone and polyacrylonitrile membrane induced significantly less beta-2 microglobulin production compared to cuprophane and slightly less compared to cellulose diacetate membrane.

Effects of heat/citric acid reprocessing on high-flux polysulfone dialyzers.

PubMed

Cornelius, Rena M; McClung, W Glenn; Richardson, Robert M A; Estridge, Charles; Plaskos, Nicholas; Yip, Christopher M; Brash, John L

2002-01-01

The surface features, morphology, and tensile properties of fibers obtained from pristine, reprocessed, and reused Fresenius Polysulfone High-Flux (Hemoflow F80A) hemodialyzers have been studied. Scanning electron microscopy of the dialyzer fibers revealed a dense skin layer on the inner surface of the membrane and a relatively thick porous layer on the outer surface. Transmission electron microscopy and atomic force microscopy showed an alteration in membrane morphology due to reprocessing and reuse, or to a deposition of blood-borne material on the membrane that is not removed with reprocessing. Fluorescent microscopy images also showed that a fluorescent material not removed by heat/citric acid reprocessing builds up with continued use of the dialyzers. The tensile properties of the dialyzer fibers were not affected by the heat/citric acid reprocessing procedure. The protein layers formed on pristine and reused hemodialyzer membranes during clinical use were also studied using sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. A considerable amount of protein was found on the blood side of single and multiple use dialyzers. Proteins adsorbed on the dialysate side of the membrane were predominantly in the molecular weight region below 30 kDa. Little protein was detected on the membranes of reprocessed hemodialyzers.

21 CFR 876.5600 - Sorbent regenerated dialysate delivery system for hemodialysis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... dialyzer. The device is used with the extracorporeal blood system and the dialyzer of the hemodialysis..., conductivity, electrolyte balance, flow rate and pressure of the dialysate, and alarms to indicate abnormal...

21 CFR 876.5600 - Sorbent regenerated dialysate delivery system for hemodialysis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... dialyzer. The device is used with the extracorporeal blood system and the dialyzer of the hemodialysis..., conductivity, electrolyte balance, flow rate and pressure of the dialysate, and alarms to indicate abnormal...

21 CFR 876.5600 - Sorbent regenerated dialysate delivery system for hemodialysis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... dialyzer. The device is used with the extracorporeal blood system and the dialyzer of the hemodialysis..., conductivity, electrolyte balance, flow rate and pressure of the dialysate, and alarms to indicate abnormal...

21 CFR 876.5600 - Sorbent regenerated dialysate delivery system for hemodialysis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... dialyzer. The device is used with the extracorporeal blood system and the dialyzer of the hemodialysis..., conductivity, electrolyte balance, flow rate and pressure of the dialysate, and alarms to indicate abnormal...

21 CFR 876.5600 - Sorbent regenerated dialysate delivery system for hemodialysis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... dialyzer. The device is used with the extracorporeal blood system and the dialyzer of the hemodialysis..., conductivity, electrolyte balance, flow rate and pressure of the dialysate, and alarms to indicate abnormal...

Urea permeation and hydrolysis through hollow fiber dialyzer immobilized with urease: storage and operation properties.

PubMed

Lin, Chi-Chang; Yang, Ming-Chien

2003-05-01

The surface of polyacrylonitrile hollow fibers was hydrolyzed and covalently bonded with urease via glutaraldehyde. Immobilized urease retained higher relative activity than native urease when storing at various pHs. The stabilities of immobilized urease to pH were higher than those of native enzyme. Immobilized urease retained 86% of initial activity after reusing 15 times at pH 7. After storing for 42d at 4 degrees C and pH 7, the immobilized urease can hydrolyze 15% of initial concentration of urea at pH 7 and 37 degrees C after 4h, while native urease lost almost its catalytic ability. The removal of urea using urease-immobilized dialyzer was demonstrated with in vitro dialysis and showed faster removing rate of urea than a regular dialyzer by 2 times. Furthermore, the improvement in the urea clearance by the urease immobilization to a dialyzer increased with the dialysate velocity.

A New Poly(Methyl Methacrylate) Membrane Dialyzer, NF, with Adsorptive and Antithrombotic Properties.

PubMed

Oshihara, Wataru; Fujieda, Hiroaki; Ueno, Yoshiyuki

2017-01-01

Poly(methyl methacrylate) (PMMA) membranes adsorb several kinds of proteins and can remove high-molecular-weight proteins, including uremic toxins, which are not removed efficiently by hemodialysis or hemodiafiltration. However, the antithrombogenicity of PMMA membranes is insufficient due to their adsorptive properties. Coagulation during hemodialysis occurs because proteins that are adsorbed to the PMMA membrane undergo structural changes and are recognized by platelets, which are then activated by adhesion to the membrane surface. In developing a new PMMA membrane dialyzer, NF, we intended to inhibit platelet adhesion to the membrane surface by suppressing the structural change in the proteins adsorbed on the membrane. In addition, we give examples of clinical trials of the NF in Japan and describe its advantages. Key Message: PMMA membrane dialyzers have been used for 40 years. The PMMA dialyzer NF can suppress the adhesion of platelets to the membrane while maintaining protein adsorption. © 2017 S. Karger AG, Basel.

Induction, transcription, synthesis, and adsorption of interleukin-1 by dialyzer membranes.

PubMed

Vaziri, N D; Wang, J; Cesario, T; Yousefi, S; Valenzuela, R; Carandang, G

1994-05-01

This study was designed to dissect the direct effect of dialyzer membrane on interleukin-1 (IL-1) induction from those of complement activation, mechanical stimulation, acetate/bicarbonate and endotoxin diffusion, and cell type interactions. To this end, a suspension of P388D1 murine macrophages in a complement-free culture medium containing 10% heat-inactivated serum, a closed-loop system consisting of tubing alone or with a hollow-fiber cuprammonium cellulose (CU) or polyacrylonitrile (PAN) dialyzer, and a roller pump were used. The dialysate compartment was filled with the same medium and capped. Cell suspension was recirculated at 300 mL/min for 3 h. Cells and supernates were separated, and adhering proteins were eluted. All samples tested negative for endotoxin. IL-1 mRNA was greatest with CU, followed by PAN and tubing alone. IL-1 in the supernate was greater with CU than with either tubing alone or PAN (P < 0.005; analysis of variance), which showed comparable values. IL-1 eluted from loops was greatest with PAN dialyzers, followed by sets with CU dialyzers and tubing alone (P < 0.001; analysis of variance). Thus, both CU and PAN membranes directly induce IL-1. However, avid adsorption by PAN attenuates the rise in circulating IL-1.

Comparison of effect of vitamin E-coated dialyzer and oral vitamin E on hemodialysis-induced Cu/Zn-superoxide dismutase.

PubMed

Akiyama, Shinichiro; Inagaki, Masahiro; Tsuji, Mayumi; Gotoh, Hiromichi; Gotoh, Tomomi; Washio, Kazunori; Gotoh, Yoshikazu; Oguchi, Katsuji

2005-01-01

We reported earlier that production of Cu/Zn-superoxide dismutase (SOD) increases markedly in hemodialysis patients but not in non-dialyzed chronic renal failure (CRF) patients. In this study, we compared the antioxidant effects of oral vitamin E supplementation (VE-PO) and vitamin E coating of a dialyzer (VE-BMD) by measuring increased Cu/Zn-SOD in hemodialysis patients. 31 hemodialysis patients were divided into two groups: 16 hemodialysis patients underwent usual dialysis with vitamin E supplementation 600 mg/day while 15 others were dialyzed using vitamin E-coated membrane for 6 months. Total plasma SOD activity was determined by NBT method, plasma Cu/Zn-SOD contents by ELISA and Cu/Zn-SOD mRNA in leukocytes by RT-PCR. VE-PO and VE-BMD showed almost comparable effects on Cu/Zn-SOD contents and its mRNA levels in hemodialysis patients. VE-PO resulted in a progressive decrease of Cu/Zn-SOD content (p < 0.001). A comparable progressive decrease was observed also in VE-BMD (p < 0.0001). Both VE-PO and VE-BMD resulted in a progressive decrease of Cu/Zn-SOD mRNA (p < 0.01), which reached the level of non-dialyzed CRF patients. Copyright (c) 2005 S. Karger AG, Basel.

Relationship of dietary factors with dialyzable iron and in vitro iron bioavailability in the meals of farm women.

PubMed

Singh, Anamika; Bains, Kiran; Kaur, Hapreet

2016-04-01

Sixty rural women with age varying between 25 and 35 were selected randomly to determine the role of dietary factors on bioavailability of iron in their diets. Food samples of selected subjects were collected for three major meals i.e. breakfast, lunch and dinner for three consecutive days. The samples were analyzed for meal constituents associated with iron absorption as well as for total and dialyzable iron. Based on dietary characteristics, the diets of the farm women were in the class of intermediate diets as per FAO/WHO classification with iron bioavailability of 8.11 %. The statistical analysis revealed that the meal constituents which were found to influence iron absorption positively were ascorbic acid and β-carotene in breakfast and only β-carotene in dinner. The meal constituents which affected iron absorption negatively were zinc and calcium in breakfast as well as lunch and phytates and NDF in dinner, however, polyphenols present in the meals of the subjects did not show any relationship with iron absorption.

What You Should Know about Dialyzer Reuse: A Guide for Hemodialysis Patients and Their Families

MedlinePlus

... Know About Dialyzer Reuse A Guide for Hemodialysis Patients and their Families What is reuse of a ... to filter fluids and wastes from a dialysis patient’s blood. Reuse of a hemodialyzer means that the ...

Selectively increasing the clearance of protein-bound uremic solutes

PubMed Central

Luo, Frank J.-G.; Plummer, Natalie S.; Hostetter, Thomas H.; Meyer, Timothy W.

2012-01-01

Background. The toxicity of bound solutes could be better evaluated if we could adjust the clearance of such solutes independent of unbound solutes. This study assessed whether bound solute clearances can be increased while maintaining urea clearance constant during the extended hours of nocturnal dialysis. Methods. Nine patients on thrice-weekly nocturnal dialysis underwent two experimental dialysis treatments 1 week apart. The experimental treatments were designed to provide the same urea clearance while providing widely different bound solute clearance. One treatment employed a large dialyzer and high dialyzate flow rate (Qd) of 800 mL/min while blood flow (Qb) was 270 mL/min. The other treatment employed a smaller dialyzer and Qd of 300 mL/min while Qb was 350 mL/min. Results. Treatment with the large dialyzer and higher Qd greatly increased the clearances of the bound solutes p-cresol sulfate (PCS: 27 ± 9 versus 14 ± 6 mL/min) and indoxyl sulfate (IS: 26 ± 8 versus 14 ± 5 mL/min) without altering the clearance of urea (204 ± 20 versus 193 ± 16 mL/min). Increasing PCS and IS clearances increased the removal of these solutes (PCS: 375 ± 200 versus 207 ± 86 mg/session; IS: 201 ± 137 versus 153 ± 74 mg/session), while urea removal was not different. Conclusions. The removal of bound solutes can thus be increased by raising the dialyzate flow and dialyzer size above the low levels sufficient to achieve target Kt/Vurea during extended treatment. Selectively increasing the clearance of bound solutes provides a potential means to test their toxicity. PMID:22231033

Exposure to potentially toxic hydrocarbons and halocarbons released from the dialyzer and tubing set during hemodialysis.

PubMed

Lee, Hyun Ji Julie; Meinardi, Simone; Pahl, Madeleine V; Vaziri, Nostratola D; Blake, Donald R

2012-10-01

Although much is known about the effect of chronic kidney failure and dialysis on the composition of solutes in plasma, little is known about their impact on the composition of gaseous compounds in exhaled breath. This study was designed to explore the effect of uremia and the hemodialysis (HD) procedure on the composition of exhaled breath. Breath samples were collected from 10 dialysis patients immediately before, during, and after a dialysis session. To determine the potential introduction of gaseous compounds from dialysis components, gasses emitted from dialyzers, tubing set, dialysate, and water supplies were collected. Prospective cohort study. 10 HD patients and 10 age-matched healthy individuals. Predictors include the dialyzers, tubing set, dialysate, and water supplies before, during, and after dialysis. Changes in the composition of exhaled breath. A 5-column/detector gas chromatography system was used to measure hydrocarbon, halocarbon, oxygenate, and alkyl nitrate compounds. Concentrations of 14 hydrocarbons and halocarbons in patients' breath rapidly increased after the onset of the HD treatment. All 14 compounds and 5 others not found in patients' breath were emitted from the dialyzers and tubing sets. Contrary to earlier reports, exhaled breath ethane concentrations in our dialysis patients were virtually unchanged during the HD treatment. Single-center study with a small sample size may limit the generalizability of the findings. The study documented the release of several potentially toxic hydrocarbons and halocarbons to patients from the dialyzer and tubing sets during the HD procedure. Because long-term exposure to these compounds may contribute to the morbidity and mortality in dialysis population, this issue should be considered in the manufacturing of the new generation of dialyzers and dialysis tubing sets. Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Resolution of Dialyzer Membrane-Associated Thrombocytopenia with Use of Cellulose Triacetate Membrane: A Case Report

PubMed Central

Olafiranye, Feyisayo; Kyaw, Win; Olafiranye, Oladipupo

2011-01-01

Blood and dialyzer membrane interaction can cause significant thrombocytopenia through the activation of complement system. The extent of this interaction determines the biocompatibility of the membrane. Although the newer synthetic membranes have been shown to have better biocompatibility profile than the cellulose-based membranes, little is known about the difference in biocompatibility between synthetic membrane and modified cellulose membrane. Herein, we report a case of a patient on hemodialysis who developed dialyzer-membrane-related thrombocytopenia with use of synthetic membrane (F200NR polysulfone). The diagnosis of dialyzer membrane-associated thrombocytopenia was suspected by the trend of platelet count before and after dialysis, and the absence of other possible causes of thrombocytopenia. We observed significant improvement in platelet count when the membrane was changed to modified cellulose membrane (cellulose triacetate). In patients at high risk for thrombocytopenia, the modified cellulose membrane could be a better alternative to the standard synthetic membranes during hemodialysis. PMID:21547252

Use of hemodialysis in meprobamate overdosage.

PubMed

Lobo, P I; Spyker, D; Surratt, P; Westervelt, F B

1977-02-01

A case of meprobamate overdosage successfully treated with hemodialysis is described. The patient was admitted 4 hours after an overdosage of meprobamate (30-40 g) deeply unconscious, hypotensive, in respiratory failure and with a serum meprobamate level of 50 mg/100 ml. Hemodialysis was instituted using a Gambro parallel flow dialyzer and a portable re-circulating dialyzate delivery system (Redy, CCi Life Systems). Meprobamate removal with hemodialysis was 672+/-167 mg/hr with a corresponding clearance of 61.97+/-9.9 ml/min. Drug removal with forced diuresis was 177+/-23.4 mg/hr. Metabolic degradation of the drug was approximately 482 mg/hr with a plasma disappearance rate of 5.2%/hr. No drug could be detected in the dialyzate fluid after its passage through the Redy re-circulating dialyzate system. Because of the rapidity of metabolic degradation of meprobamate, we feel that hemodialysis should be reserved for severe clinical intoxication and either compromised normal excretory routes or progressive clinical deterioration.

In vitro dialyzability of essential minerals from white and whole grain pasta.

PubMed

Vignola, María Belén; Bustos, Mariela Cecilia; Pérez, Gabriela Teresa

2018-11-01

The aim of the present investigation was to study the in vitro mineral dialyzability of pasta made with white and whole-grain flours obtained from two genotypes (Klein Guerrero and Baguette Premium 11) with different mineral contents. Pasta samples were made from white flour (FP), and whole grain flour from cyclonic mill (WFAP) and blade mill (WFBP). Mineral content and in vitro digestion were determined on all samples to study starch variation and mineral dialyzability. Whole-grain pasta contained significantly higher amounts of minerals than FP, since bran and embryo are richer in minerals than endosperm. In addition to the low content of mineral composition observed in FP, the dialyzability of some minerals (Cu, Fe, Mg and Zn) was higher than whole-grain pasta even when the percentage of starch hydrolyzed after intestinal digestion was higher than FP. These results can also be useful for developing wheat-based products rich in the desired minerals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cuprophane but not synthetic membrane induces increases in serum tumor necrosis factor-alpha levels during hemodialysis.

PubMed

Canivet, E; Lavaud, S; Wong, T; Guenounou, M; Willemin, J C; Potron, G; Chanard, J

1994-01-01

Cytokine synthesis and secretion by blood mononuclear cells is a well-documented phenomenon in hemodialyzed patients. The present study was conducted in 17 chronically hemodialyzed patients to test the relative effect of uremic toxicity, membrane biocompatibility, dialysate composition, and the risk of endotoxinemia on the serum level of tumor necrosis factor-alpha (TNF-alpha). The only significant parameter that influenced circulating TNF-alpha was the chemical characteristics of the dialyzer membrane. Tumor necrosis factor-alpha levels significantly increased during the session with cuprophane, whereas they decreased with AN69. The TNF-alpha increase was documented whatever the dialysate buffer and the presence or absence (negative Limulus amoebocyte lysate test) of endotoxin in the dialysate. In the subgroup of patients treated with a contaminated dialysate and AN69, none had clinical symptoms and the central body temperature remained constant throughout the session. In these patients, serum TNF-alpha levels did not change after priming the dialyzer with sterile saline. In conclusion, the serum TNF-alpha level during hemodialysis appears to be modulated by biocompatibility, permeability, and binding properties of dialysis membrane rather than dialysate composition. Endotoxin in the dialysate did not result in positive TNF-alpha balance no matter what its possible priming effect on mononucleated blood cells.

[Possibilities of dialysis therapy in irreversible renal failure in rheumatoid arthritis with secondary amyloidosis].

PubMed

Vachtenheim, J; Tocík, J; Novák, Z; Zeman, P

1990-11-01

The authors discuss their initial experience with the treatment of secondary amyloidosis in rheumatoid arthritis with irreversible renal failure in patients included in a regular dialyzation programme. The hitherto assembled 15-month experience justifies the inclusion of patients with this cause of irreversible renal failure in a dialyzation programme. The reverse is not only wrong from the medical aspect but is inhuman and interferes with the life of families of these patients. Although the procedure during a regular dialyzation programme of these patients with rheumatoid arthritis with secondary amyloidosis is more complicated, more pretentious and more responsible, it is our medical duty to carry this burden together with the patient.

21 CFR 876.5820 - Hemodialysis system and accessories.

Code of Federal Regulations, 2010 CFR

2010-04-01

... chair without a scale, the dialyzer holder set, dialysis tie gun and ties, and hemodialysis start/stop..., dialyzer holder set, and dialysis tie gun and ties. The devices subject to this paragraph (b)(2) are exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the...

Effects of dialyzer membrane on serum albumin levels in patients receiving hemodialysis.

PubMed

Rault, R M

2003-11-01

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.

Results of the HepZero study comparing heparin-grafted membrane and standard care show that heparin-grafted dialyzer is safe and easy to use for heparin-free dialysis.

PubMed

Laville, Maurice; Dorval, Marc; Fort Ros, Joan; Fay, Renaud; Cridlig, Joëlle; Nortier, Joëlle L; Juillard, Laurent; Dębska-Ślizień, Alicja; Fernández Lorente, Loreto; Thibaudin, Damien; Franssen, Casper; Schulz, Michael; Moureau, Frédérique; Loughraieb, Nathalie; Rossignol, Patrick

2014-12-01

Heparin is used to prevent clotting during hemodialysis, but heparin-free hemodialysis is sometimes needed to decrease the risk of bleeding. The HepZero study is a randomized, multicenter international controlled open-label trial comparing no-heparin hemodialysis strategies designed to assess non-inferiority of a heparin grafted dialyzer (NCT01318486). A total of 251 maintenance hemodialysis patients at increased risk of hemorrhage were randomly allocated for up to three heparin-free hemodialysis sessions using a heparin-grafted dialyzer or the center standard-of-care consisting of regular saline flushes or pre-dilution. The first heparin-free hemodialysis session was considered successful when there was neither complete occlusion of air traps or dialyzer, nor additional saline flushes, changes of dialyzer or bloodlines, or premature termination. The current standard-of-care resulted in high failure rates (50%). The success rate in the heparin-grafted membrane arm was significantly higher than in the control group (68.5% versus 50.4%), which was consistent for both standard-of-care modalities. The absolute difference between the heparin-grafted membrane and the controls was 18.2%, with a lower bound of the 90% confidence interval equal to plus 7.9%. The hypothesis of the non-inferiority at the minus 15% level was accepted, although superiority at the plus 15% level was not reached. Thus, use of a heparin-grafted membrane is a safe, helpful, and easy-to-use method for heparin-free hemodialysis in patients at increased risk of hemorrhage.

Characterization of biosurfactants produced by Lactobacillus spp. and their activity against oral streptococci biofilm.

PubMed

Ciandrini, Eleonora; Campana, Raffaella; Casettari, Luca; Perinelli, Diego R; Fagioli, Laura; Manti, Anita; Palmieri, Giovanni Filippo; Papa, Stefano; Baffone, Wally

2016-08-01

Lactic acid bacteria (LAB) can interfere with pathogens through different mechanisms; one is the production of biosurfactants, a group of surface-active molecules, which inhibit the growth of potential pathogens. In the present study, biosurfactants produced by Lactobacillus reuteri DSM 17938, Lactobacillus acidophilus DDS-1, Lactobacillus rhamnosus ATCC 53103, and Lactobacillus paracasei B21060 were dialyzed (1 and 6 kDa) and characterized in term of reduction of surface tension and emulsifying activity. Then, aliquots of the different dialyzed biosurfactants were added to Streptococcus mutans ATCC 25175 and Streptococcus oralis ATCC 9811 in the culture medium during the formation of biofilm on titanium surface and the efficacy was determined by agar plate count, biomass analyses, and flow cytometry. Dialyzed biosurfactants showed abilities to reduce surface tension and to emulsifying paraffin oil. Moreover, they significantly inhibited the adhesion and biofilm formation on titanium surface of S. mutans and S. oralis in a dose-dependent way, as demonstrated by the remarkable decrease of cfu/ml values and biomass production. The antimicrobial properties observed for dialyzed biosurfactants produced by the tested lactobacilli opens future prospects for their use against microorganisms responsible of oral diseases.

Variation in fistula use across dialysis facilities: is it explained by case-mix?

PubMed

Tangri, Navdeep; Moorthi, Ranjani; Tighiouhart, Hocine; Meyer, Klemens B; Miskulin, Dana C

2010-02-01

Arteriovenous fistulas (AVFs) remain the preferred vascular access for hemodialysis patients. Dialysis facilities that fail to meet Centers for Medicare & Medicaid Services goals cite patient case-mix as a reason for low AVF prevalence. This study aimed to determine the magnitude of the variability in AVF usage across dialysis facilities and the extent to which patient case-mix explains it. The vascular access used in 10,112 patients dialyzed at 173 Dialysis Clinic Inc. facilities from October 1 to December 31, 2004, was evaluated. The access in use was considered to be an AVF if it was used for >70% of hemodialysis treatments. Mixed-effects models with a random intercept for dialysis facilities evaluated the effect of facilities on AVF usage. Sequentially adjusted multivariate models measured the extent to which patient factors (case-mix) explain variation across facilities in AVF rates. 3787 patients (38%) were dialyzed using AVFs. There was a significant facility effect: 7.6% of variation in AVF use was attributable to facility. This was reduced to 7.1% after case-mix adjustment. There were no identified specific facility-level factors that explained the interfacility variation. AVF usage varies across dialysis facilities, and patient case-mix did not reduce this variation. In this study, 92% of the total variation in AVF usage was due to patient factors, but most were not measurable. A combination of patient factors and process indicators should be considered in adjudicating facility performance for this quality indicator.

Symptom Prevalence and the Negative Emotional States in End-Stage Renal Disease Patients with or without Renal Replacement Therapy: A Cross-Sectional Analysis.

PubMed

Wan Zukiman, Wan Zul Haikal; Yaakup, Hayati; Zakaria, Nor Fadhlina; Shah, Shamsul Azhar Bin

2017-10-01

Limited comparative data are available on the symptom severity and burden of dialyzed versus nondialyzed end-stage renal disease (ESRD) patients and their association with negative emotional states. To investigate the prevalence of symptom burden and severity of ESRD patients and correlate the findings with their psychological status. This was a cross-sectional study of dialyzed (N = 87) and nondialyzed (N = 100) patients. The symptom burden and severity were determined using the Dialysis Symptom Index (DSI) and the psychological assessment using Depression Anxiety Stress Scale 21 (DASS-21). Symptom severity evaluated using the DSI was comparable in both groups with fatigue as the most common symptom (n = 141, 75.4%), followed by sleep-related, sexual dysfunction, and dry skin problems. The symptom burden for worrying, dry skin and mouth, decreased appetite, numbness, and leg swelling were significant in not dialyzed group (p < 0.05).The DASS-21 scores revealed that 11% of patients were depressed, 21.8% were stressed, and 15.6% were anxious (p < 0.030). The prevalence of psychological disturbances was associated with high symptom burden regardless of their treatment options (p < 0.005). Dialyzed patients showed a positive psychological status trend on DASS-21 assessment. The not dialyzed group consisted of 34% from comprehensive conservative group, 26% of choice-restricted conservative care, and 40% with no definitive future plan. There was no difference in the prevalence of symptom burden and severity, irrespective of the type of treatment. Psychological disturbances were associated with higher symptom burden and severity and, therefore, should be screened thoroughly to achieve optimal ESRD management.

Activation of Basophils Is a New and Sensitive Marker of Biocompatibility in Hemodialysis

PubMed Central

Aljadi, Zenib; Mansouri, Ladan; Nopp, Anna; Paulsson, Josefin M; Winqvist, Ola; Russom, Aman; Ståhl, Mårten; Hylander, Britta; Jacobson, Stefan H; Lundahl, Joachim

2014-01-01

The hemodialysis procedure involves contact between peripheral blood and the surface of dialyzer membranes, which may lead to alterations in the pathways of innate and adaptive immunity. We aimed to study the effect of blood–membrane interaction on human peripheral basophils and neutrophils in hemodialysis with high- and low-permeability polysulfone dialyzers. The surface expression of CD203c (basophil selection marker) and CD63 (activation marker) after activation by the bacterial peptide formyl-methionyl-leucyl-phenylalanine (fMLP) or anti-Fcε receptor I (FcεRI) antibody and the absolute number of basophils was investigated before and after hemodialysis with each of the dialyzers. Moreover, the expression on neutrophils of CD11b, the CD11b active epitope, and CD88 was analyzed in the same groups of individuals. The expression of CD63 in basophils following activation by fMLP was significantly higher in the patient group compared with that in healthy controls, but no differences were observed after activation by anti-FcεRI. During the hemodialysis procedure, the low-flux membrane induced up-regulation of CD63 expression on basophils, while passage through the high-flux membrane did not significantly alter the responsiveness. In addition, the absolute number of basophils was unchanged after hemodialysis with either of the dialyzers and compared with healthy controls. We found no significant differences in the expression of the neutrophil activation markers (CD11b, the active epitope of CD11b, and CD88) comparing the two different dialyzers before and after dialysis and healthy controls. Together, these findings suggest that alterations in basophil activity may be a useful marker of membrane bioincompatibility in hemodialysis. PMID:24712758

Antioxidant therapy by oral vitamin E and vitamin E-coated dialyzer in CAPD and haemodialysis patients.

PubMed

Mydlík, M; Derzsiová, K; Rácz, O; Sipulová, A; Lovásová, E

2006-01-01

Oxidative stress, increased lipid peroxidation, and impaired function of antioxidant system may contribute to the accelerated development of atherosclerosis in chronic renal failure patients during renal replacement therapy. The aim of the study was to investigate the influence of oral vitamin E (400 mg/day) in 14 patients who underwent continuous ambulatory peritoneal dialysis (CAPD) and effects of the vitamin E-coated dialyzer in 14 haemodialysis patients on several antioxidant biochemical parameters. Six-week treatment with oral vitamin E in CAPD patients and three-month treatment using vitamin E-coated dialyzer in haemodialysis patients led to the significant decrease of plasma malondialdehyde, to the increase of plasma vitamin E and to the increase of erythrocyte vitamin E in haemodialysis patients. No significant changes of erythrocyte antioxidant enzyme--superoxide dismutase, glutathione peroxidase and catalase were found during the both types of antioxidant therapy. At the end of the third month of haemodialysis study the significant increase of erythrocyte glutathione in haemodialysis patients was found, but that value was significantly lower as normal range. Six-week interruption of the administration of oral vitamin E in CAPD patients led to the significant decrease of erythrocyte superoxide dismutase and plasma vitamin E. Ten-week interruption of the use of vitamin E-coated dialyzer led to the significant increase of plasma malondialdehyde and to the decrease of plasma and erythrocyte vitamin E in haemodialysis patients, near to the values at the beginning of the study. Our study confirmed the beneficial effect of oral administration of vitamin E and the use of vitamin E-coated dialyzer against oxidative stress in CAPD and haemodialysis patients.

Free heme and sickle hemoglobin polymerization

NASA Astrophysics Data System (ADS)

Uzunova, Veselina V.

This work investigates further the mechanism of one of the most interesting of the protein self-assembly systems---the polymerization of sickle hemoglobin and the role of free heme in it. Polymerization of sickle hemoglobin is the primary event in the pathology of a chronic hemolytic condition called sickle cell anemia with complex pathogenesis, unexplained variability and symptomatic treatment. Auto-oxidation develops in hemoglobin solutions exposed to room temperature and causes release of ferriheme. The composition of such solutions is investigated by mass spectrometry. Heme dimers whose amount corresponds to the initial amounts of heme released from the protein are followed. Differences in the dimer peak height are established for hemoglobin variants A, S and C and depending on the exposure duration. The effects of free heme on polymerization kinetics are studied. Growth rates and two characteristic parameters of nucleation are measured for stored Hb S. After dialysis of polymerizing solutions, no spherulites are detected at moderately high supersaturation and prolonged exposure times. The addition of 0.16-0.26 mM amounts of heme to dialyzed solutions leads to restoration of polymerization. The measured kinetic parameters have higher values compared to the ones before dialysis. The amount of heme in non-dialyzed aged solution is characterized using spectrophotometry. Three methods are used: difference in absorbance of dialyzed and non-dialyzed solutions, characteristic absorbance of heme-albumin complex and absorbance of non-dialyzed solutions with added potassium cyanide. The various approaches suggest the presence of 0.12 to 0.18 mM of free ferriheme in such solutions. Open questions are whether the same amounts of free heme are present in vivo and whether the same mechanism operates intracellulary. If the answer to those questions is positive, then removal of free heme from erythrocytes can influence their readiness to sickle.

Analytical and Finite Element Modeling of Nanomembranes for Miniaturized, Continuous Hemodialysis

PubMed Central

Burgin, Tucker; Johnson, Dean; Chung, Henry; Clark, Alfred; McGrath, James

2015-01-01

Hemodialysis involves large, periodic treatment doses using large-area membranes. If the permeability of dialysis membranes could be increased, it would reduce the necessary dialyzer size and could enable a wearable device that administers a continuous, low dose treatment of chronic kidney disease. This paper explores the application of ultrathin silicon membranes to this purpose, by way of analytical and finite element models of diffusive and convective transport of plasma solutes during hemodialysis, which we show to be predictive of experimental results. A proof-of-concept miniature nanomembrane dialyzer design is then proposed and analytically predicted to clear uremic toxins at near-ideal levels, as measured by several markers of dialysis adequacy. This work suggests the feasibility of miniature nanomembrane-based dialyzers that achieve therapeutic levels of uremic toxin clearance for patients with kidney failure. PMID:26729179

Hemodialysis-associated neutropenia and hypoxemia: the effect of dialyzer membrane materials.

PubMed

Hakim, R M; Lowrie, E G

1982-01-01

The fall in white blood cells (WBC) and arterial oxygen pressure that occurs during hemodialysis was investigated as a function of different dialysis membranes and different sterilization methods. 8 chronic hemodialysis patients were studied and each was dialyzed with three different membranes: cellulosic hollow fiber, polyacrylonitrile flat sheet and polymethylmethacrylate hollow fiber. Each dialyzer was studied with a dry sterilization method and after formalin treatment. Arterialized blood gas, bicarbonate and WBC were drawn at various intervals throughout dialysis. The effect of the sterilization method was minimal. Cellulosic membranes were shown to cause significantly more neutropenia (p less than 0.001) and hypoxemia (p less than 0.01) than the other two membranes. No significant differences was seen in pH, PCO2 and bicarbonate. The results indicate differences in biocompatibility between different membranes. Clinical implications are discussed.

Comparison of hemodialysis with medium cut-off dialyzer and on-line hemodiafiltration on the removal of small and middle-sized molecules
.

PubMed

Belmouaz, Mohamed; Diolez, Jeremy; Bauwens, Marc; Duthe, Fabien; Ecotiere, Laure; Desport, Estelle; Bridoux, Frank

2018-01-01

Recent data suggest that the use of medium cut-off (MCO) dialyzers in hemodialysis (HD) promotes greater clearance and reduction ratio (RR) for myoglobin and other large-sized molecules than on-line hemodiafiltration (ol-HDF), but its effects on β2-microglobulin are not clear. We compared RR and clearances of small and middle-sized molecules between high-flux ol-HDF and MCO (Theranova) dialyzer in HD (MCO-HD) as well as nutritional parameters. We retrospectively analyzed 10 patients treated first with ol-HDF who were thereafter switched to MCO-HD over a 1-year period. Three dialysis sessions in each 6-month period were examined. We calculated RR and clearance of small and middle-sized molecules. There was no significant difference between ol-HDF and MCO-HD for median serum albumin and prealbumin level, mean KT/V, mean urea and creatinine RR, mean β2-microglobulin (81 ± 5 vs. 81 ± 6%, p = 0.72) and myoglobin (60 ± 9% vs. 61 ± 7%, p = 0.59), RR or clearances. The use of MCO (Theranova) dialyzer in HD produces similar removal of urea, creatinine, β2-microglobulin and myoglobin as does ol-HDF, with good tolerance profile and without modification of nutritional status.
.

Vitamin E as a functional and biocompatibility modifier of synthetic hemodialyzer membranes: an overview of the literature on vitamin E-modified hemodialyzer membranes.

PubMed

Piroddi, Marta; Pilolli, Francesca; Aritomi, Masaharu; Galli, Francesco

2012-01-01

Along with one century of history, research has provided many solutions for hemodialysis (HD) biomaterials, encompassing several generations of copolymers that have found wide application in the development of hollow-fiber dialyzer membranes. Polysulfone-based biomaterials have gained increasing consideration and are now the gold standard in the production of biocompatible hemodialyzers. However, even the highest biocompatibility now available cannot exclude that dialyzer membranes and the overall extracorporeal circulation may produce at the subclinical level immunoinflammatory reactions and thus an increased cardiovascular risk of patients on regular HD therapy. The lipophilic antioxidant and radical scavenger vitamin E has been used (as α-tocopherol) to modify cellulosic and synthetic hollow-fiber membranes with the ultimate goal to neutralize harmful reactive species and to mimic lipid structures of blood cell plasmalemma and lipoprotein particles. Besides filtration and biocompatibility, this modifier has introduced a third function of dialyzer membranes, namely 'antioxidant bioactivity'. Vitamin E can also serve as a template molecule to produce synthetic redox-active and -silent (non-antioxidant) modifiers for future generations of dialyzer membranes. This mini-review article describes the evolution of vitamin E-derived copolymers as a generation of biomaterials that has offered a clinical challenge and still represents a chance to further improving the quality of HD therapy. Copyright © 2012 S. Karger AG, Basel.

Neutrophil gelatinase-associated lipocalin (NGAL) and matrix metalloproteinases as novel stress markers in children and young adults on chronic dialysis.

PubMed

Musiał, Kinga; Zwolińska, Danuta

2011-03-01

Phenomena related to chronic kidney disease, such as atherosclerosis, aggravate with the introduction of dialysis. Matrix metalloproteinases (MMP) and factors modifying their activity, such as their tissue inhibitors (TIMP) or neutrophil gelatinase-associated lipocalin (NGAL), take part in the matrix turnover and the endothelial damage characteristic for atherogenesis. However, there are no data on the associations between these parameters and other known pro-atherogenic factors, or on the impact of various dialysis modalities on them. The aim of our study was to assess the serum concentrations of NGAL, MMP-7, MMP-9, and TIMP-1, as well as their correlations with human heat shock proteins (Hsp90α, anti-Hsp60), endothelial dysfunction (sE-selectin), and inflammation (hsCRP) in pediatric patients chronically dialyzed. Twenty-two children on automated peritoneal dialysis (APD), 17 patients on hemodialysis (HD) and 24 controls were examined. The serum concentrations of NGAL, MMP-7, MMP-9, TIMP-1, Hsp90α, anti-Hsp60, and sE-selectin were assessed by enzyme-linked immunosorbent assay (ELISA). The median values of NGAL, MMP-7, MMP-9, TIMP-1, and MMP-9/NGAL ratio were significantly elevated in all dialyzed children vs. controls and were higher in HD than in APD. The values of MMP-9/TIMP-1 and MMP-7/TIMP-1 ratios in the HD subjects were lower than those in the APD children. Hsp90α and anti-Hsp60 predicted the values of NGAL, MMPs, and TIMP-1. Additionally, sE-selectin was a predictor of NGAL levels, whereas NGAL predicted the MMP and TIMP-1 concentrations. The increased concentrations of examined parameters indicate the dysfunction of MMP/TIMP/NGAL system in the dialyzed children, more pronounced on hemodialysis. The discrepancies between dialysis modalities and correlations with heat shock proteins (HSPs) suggest that NGAL may be considered a novel stress protein, whereas MMP-7, MMP-9, and TIMP-1 may be regarded as indicators of stress response in the pediatric population on chronic dialysis.

Polyester polymer alloy as a high-performance membrane.

PubMed

Igoshi, Tadaaki; Tomisawa, Narumi; Hori, Yoshinori; Jinbo, Yoichi

2011-01-01

Polyester polymer alloy (PEPA) membrane is developed as a synthetic polymermembrane. It consists of two polymers - polyethersulfone (PES) and polyarylate (PAR).The pore size in membrane can be controlled by a blend ratio of PES and PAR. One unique characteristic is that PEPA membrane has three layers of a skin layer on the inner surface, a porous layer in the membrane, and a skin layer on the outer surface, respectively. The permeability of water and substances is controlled by the skin layer on the inner surface. PEPA membrane dialyzer can be adequately considered as a high-performance dialyzer. Furthermore, the skin layer on the outer surface can block endotoxin from the dialysis fluid side. PEPA membrane can therefore be used as an endotoxin-retentive filter. The other unique characteristic is that each amount of albumin loss or β2-microglobulin removal can be controlled by an additive amount of polyvinylpyrrolidone. This means that the PEPA dialyzer can be clinically used to meet the conditions of the patient. Copyright © 2011 S. Karger AG, Basel.

Continuous cognitive improvement 1 year following successful kidney transplant.

PubMed

Harciarek, Michał; Biedunkiewicz, Bogdan; Lichodziejewska-Niemierko, Monika; Dębska-Ślizień, Alicja; Rutkowski, Bolesław

2011-06-01

Successful kidney transplantation was recently shown to lead to improvement in the cognitive performance of patients on chronic dialysis. To examine whether the early cognitive benefits of transplantation continue to develop over time, along with the patients' ongoing recovery, we addressed these questions in a prospective controlled study of 27 dialyzed patients who subsequently received a kidney transplant, 18 dialyzed patients awaiting kidney transplant, and 30 matched controls without kidney disease. Overall, successful kidney transplant contributed to a statistically significant improvement in performance on tests of motor/psychomotor speed, visual planning, memory, and abstract reasoning tested 1 year later. We also studied whether the cognitive performance of patients maintained on dialysis is stable or declines over time and found that it actually declined over this time even in adequately dialyzed patients. Measures of memory functions were particularly affected. This study indicates that the early beneficial effects of transplantation are not transient and were still evident 1 year following transplantation.

Bioaccessibility of Ca, Cu, Fe, Mg, Zn, and crude protein in beef, pork and chicken after thermal processing.

PubMed

Menezes, Eveline A; Oliveira, Aline F; França, Celia J; Souza, Gilberto B; Nogueira, Ana Rita A

2018-02-01

The bioaccessibility of Ca, Cu, Fe, Mg, Zn, and crude protein was evaluated after submitting beef, pork, and chicken to five different thermal treatments. The bioaccessibility of crude protein and metals were simulated by using in vitro enzymatic digestion with a gastric fluid solution and dialysability approach. Inductively coupled plasma optical spectrometry was used to quantify the dialyzable fraction and the total mineral content after microwave-assisted digestion. Graphite furnace atomic absorption spectrometry quantified Cu in chicken dialyzable fraction. The increase of temperature and heat exposure period decreased the protein bioaccessibility. Considering the total and dialyzable fraction, beef is an important source of Cu, Fe, Mg, and Zn to the human diet. The results of Fourier-transform infrared spectroscopy indicated physical changes in the treated samples related to protein denaturation, which was probably responsible for the decreased bioaccessibility of minerals and protein, mainly at higher temperatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improvement of blood compatibility on polysulfone-polyvinylpyrrolidone blend films as a model membrane of dialyzer by physical adsorption of recombinant soluble human thrombomodulin (ART-123).

PubMed

Omichi, Masaaki; Matsusaki, Michiya; Maruyama, Ikuro; Akashi, Mitsuru

2012-01-01

ART-123 is a recombinant soluble human thrombomodulin (hTM) with potent anticoagulant activity, and is available for developing antithrombogenic surfaces by immobilization. We focused on improving blood compatibility on the dialyzer surface by the physical adsorption of ART-123 as a safe yet simple method without using chemical reagents. The physical adsorption mechanism and anticoagulant activities of adsorbed hTM on the surface of a polysulfone (PSF) membrane containing polyvinylpyrrolidone (PVP) as a model dialyzer were investigated in detail. The PVP content of the PSF-PVP films was saturated at 20 wt% after immersion in Tris-HCl buffer, even with the addition of over 20 wt% PVP. The surface morphology of the PSF-PVP films was strongly influenced by the PVP content, because PVP covered the outermost surface of the PSF-PVP films. The adsorption speed of hTM slowed dramatically with increasing PVP content up to 10 wt%, but the maximum adsorption amount of hTM onto the PSF-PVP film surface was almost the same, regardless of the PVP content. The PSF-PVP film with the physically adsorbed hTM showed higher protein C activity as compared to the PSF film, it showed excellent blood compatibility due to the protein C activity and the inhibition properties of platelet adhesion. The physical adsorption of hTM can be useful as a safe yet simple method to improve the blood compatibility of a dialyzer surface.

Effects of reuse and bleach/formaldehyde reprocessing on polysulfone and polyamide hemodialyzers.

PubMed

Cornelius, Rena M; McClung, W Glenn; Barre, Paul; Esguerra, Fe; Brash, John L

2002-01-01

The surface features, morphology, and blood interactions of fibers from pristine, bleach/formaldehyde reprocessed, and reused Fresenius Polysulfone High Flux (Hemoflow F80B) hemodialyzers and Gambro Polyflux 21S Polyamide hemodialyzers have been studied. SEM images of fibers from both hemodialyzer types revealed a dense skin layer on the inner surface and a relatively thick porous layer on the outer surface. The 21S polyamide support layer consisted of interconnected highly porous structures. Environmental scanning electron microscopy and atomic force microscopy images of both membrane types showed alterations in morphology due to reprocessing and reuse; however the changes were more marked for the 21S polyamide dialyzers. Fluorescence microscopy images showed only minimal fluorescence associated with the fibers after patient use and reprocessing, suggesting that blood derived deposits were removed by processing. The protein layers formed on pristine and reused hemodialyzer membranes during clinical use were studied using SDS-PAGE and immunoblotting. Before bleach/formaldehyde treatment, protein layers of considerable amount and complexity were found on the blood side of singly and multiply used dialyzers. Proteins adsorbed on the dialysate side were predominantly in the molecular mass region below 30 kDa. However, some higher molecular mass proteins were detected on the dialysate side of the 21 S polyamide dialyzers. Very little protein was detected on dialyzers that were treated with bleach/formaldehyde after dialysis, regardless of whether they had been used/reprocessed once or 12 times.

Uremic Pruritus, Dialysis Adequacy, and Metabolic Profiles in Hemodialysis Patients: A Prospective 5-Year Cohort Study

PubMed Central

Chen, Hung-Yuan; Chiu, Yen-Ling; Hsu, Shih-Ping; Pai, Mei-Fen; Ju-YehYang; Lai, Chun-Fu; Lu, Hui-Min; Huang, Shu-Chen; Yang, Shao-Yu; Wen, Su-Yin; Chiu, Hsien-Ching; Hu, Fu-Chang; Peng, Yu-Sen; Jee, Shiou-Hwa

2013-01-01

Background Uremic pruritus is a common and intractable symptom in patients on chronic hemodialysis, but factors associated with the severity of pruritus remain unclear. This study aimed to explore the associations of metabolic factors and dialysis adequacy with the aggravation of pruritus. Methods We conducted a 5-year prospective cohort study on patients with maintenance hemodialysis. A visual analogue scale (VAS) was used to assess the intensity of pruritus. Patient demographic and clinical characteristics, laboratory parameters, dialysis adequacy (assessed by Kt/V), and pruritus intensity were recorded at baseline and follow-up. Change score analysis of the difference score of VAS between baseline and follow-up was performed using multiple linear regression models. The optimal threshold of Kt/V, which is associated with the aggravation of uremic pruritus, was determined by generalized additive models and receiver operating characteristic analysis. Results A total of 111 patients completed the study. Linear regression analysis showed that lower Kt/V and use of low-flux dialyzer were significantly associated with the aggravation of pruritus after adjusting for the baseline pruritus intensity and a variety of confounding factors. The optimal threshold value of Kt/V for pruritus was 1.5 suggested by both generalized additive models and receiver operating characteristic analysis. Conclusions Hemodialysis with the target of Kt/V ≥1.5 and use of high-flux dialyzer may reduce the intensity of pruritus in patients on chronic hemodialysis. Further clinical trials are required to determine the optimal dialysis dose and regimen for uremic pruritus. PMID:23940749

Regional citrate anticoagulation in hemodialysis: an observational study of safety, efficacy, and effect on calcium balance during routine care.

PubMed

Singer, Richard F; Williams, Oliver; Mercado, Chari; Chen, Bonny; Talaulikar, Girish; Walters, Giles; Roberts, Darren M

2016-01-01

Regional citrate hemodialysis anticoagulation is used when heparin is contraindicated, but most protocols require large infusions of calcium and frequent intradialytic plasma ionized calcium measurements. The objective of this study was to determine the safety, efficacy, and effect on calcium balance of regional citrate anticoagulation using sparse plasma ionized calcium sampling. The design of this study was observational. The setting of this study was the hospital hemodialysis center. The subjects of this study were the hospital hemodialysis patients. Dialysate calcium concentration by atomic absorption spectroscopy and total dialysate weight were used as measurements. Regional citrate anticoagulation was introduced using zero calcium dialysate, pre-dialyzer citrate infusion, and post-dialyzer calcium infusion. Infusions were adjusted based on pre- and post-dialyzer calcium measurements obtained at least twice during a 4-h dialysis. The protocol was simplified after the first 357 sessions to dispense with post-dialyzer calcium measurements. Heparin-anticoagulated sessions were performed using acetate-acidified 1.25 mmol/L calcium or citrate-acidified 1.5 mmol/L calcium dialysate. Calcium balance assessment was by complete dialysate recovery. Safety and efficacy were assessed prospectively using a point-of-care database to record ionized calcium and clinical events. Groups were compared using t test, ANOVA, Wilcoxon rank sum, or Kruskal-Wallis as appropriate. Seventy-five patients received regional citrate-anticoagulated dialysis over 1051 dialysis sessions. Of these, 357 dialysis sessions were performed using the original citrate anticoagulation protocol and 694 using the simplified protocol. Dialysis was effective and safe. Only 3 dialyzers clotted; 1 patient suffered symptomatic hypercalcemia and none suffered symptomatic hypocalcemia. Calcium balance was assessed in 15 regional citrate-anticoagulated dialysis sessions and 30 heparin-anticoagulated sessions. The median calcium loss was 0.8 mmol/h dialyzed in both groups (p = 0.43), and end of treatment ionized calcium was the same in both groups (1.07 ± 0.04 mmol/L). Our findings for calcium balance, efficacy, and safety are valid only for the protocol studied, which excluded patient with severe liver dysfunction. Regional citrate dialysis can be performed safely and effectively using a sparse plasma calcium sampling protocol. The calcium balance induced by this protocol is not different to that seen in standard heparin-anticoagulated dialysis, but in the absence of prospective studies, it is unknown whether this is optimal for patient care.

Clinical evaluation of Altra-Flux 140 cellulose diacetate hollow-fiber dialyzer.

PubMed

Kes, P; Ratković-Gusić, I; Prsa, M

1996-01-01

Clinical evaluation of Altra-Flux 140, a new Pliva hollow-fiber type dialyzer showed the clearances and removal rate of small molecular weight solutes to be satisfactory during 4-hour dialysis. The ultrafiltration rate was high, but acceptable when used with volumetric-controlled hemodialysis delivery systems. Biocompatibility was good, and there were no intradialytic symptoms in patients, attributable to the use of Altra-Flux 140. In general, no residual blood was detected. Handling of Altra-Flux 140 was found to be easy and the membrane strength adequate.

Portable Nitric Oxide (NO) Generator Based on Electrochemical Reduction of Nitrite for Potential Applications in Inhaled NO Therapy and Cardiopulmonary Bypass Surgery.

PubMed

Qin, Yu; Zajda, Joanna; Brisbois, Elizabeth J; Ren, Hang; Toomasian, John M; Major, Terry C; Rojas-Pena, Alvaro; Carr, Benjamin; Johnson, Thomas; Haft, Jonathan W; Bartlett, Robert H; Hunt, Andrew P; Lehnert, Nicolai; Meyerhoff, Mark E

2017-11-06

A new portable gas phase nitric oxide (NO) generator is described for potential applications in inhaled NO (INO) therapy and during cardiopulmonary bypass (CPB) surgery. In this system, NO is produced at the surface of a large-area mesh working electrode by electrochemical reduction of nitrite ions in the presence of a soluble copper(II)-ligand electron transfer mediator complex. The NO generated is then transported into gas phase by either direct purging with nitrogen/air or via circulating the electrolyte/nitrite solution through a gas extraction silicone fiber-based membrane-dialyzer assembly. Gas phase NO concentrations can be tuned in the range of 5-1000 ppm (parts per million by volume for gaseous species), in proportion to a constant cathodic current applied between the working and counter electrodes. This new NO generation process has the advantages of rapid production times (5 min to steady-state), high Faraday NO production efficiency (ca. 93%), excellent stability, and very low cost when using air as the carrier gas for NO (in the membrane dialyzer configuration), enabling the development of potentially portable INO devices. In this initial work, the new system is examined for the effectiveness of gaseous NO to reduce the systemic inflammatory response (SIR) during CPB, where 500 ppm of NO added to the sweep gas of the oxygenator or to the cardiotomy suction air in a CPB system is shown to prevent activation of white blood cells (granulocytes and monocytes) during extracorporeal circulation with cardiotomy suction conducted with five pigs.

Relationship between platelet count and hemodialysis membranes

PubMed Central

Nasr, Rabih; Saifan, Chadi; Barakat, Iskandar; Azzi, Yorg Al; Naboush, Ali; Saad, Marc; Sayegh, Suzanne El

2013-01-01

Background One factor associated with poor outcomes in hemodialysis patients is exposure to a foreign membrane. Older membranes are very bioincompatible and increase complement activation, cause leukocytosis by activating circulating factors, which sequesters leukocytes in the lungs, and activates platelets. Recently, newer membranes have been developed that were designed to be more biocompatible. We tested if the different “optiflux” hemodialysis membranes had different effects on platelet levels. Methods Ninety-nine maintenance hemodialysis patients with no known systemic or hematologic diseases affecting their platelets had blood drawn immediately prior to, 90 minutes into, and immediately following their first hemodialysis session of the week. All patients were dialyzed using a Fresenius Medical Care Optiflux polysulfone membrane F160, F180, or F200 (polysulfone synthetic dialyzer membranes, 1.6 m2, 1.8 m2, and 2.0 m2 surface area, respectively, electron beam sterilized). Platelet counts were measured from each sample by analysis using a CBC analyzer. Results The average age of the patients was 62.7 years; 36 were female and 63 were male. The mean platelet count pre, mid, and post dialysis was 193 (standard deviation ±74.86), 191 (standard deviation ±74.67), and 197 (standard deviation ±79.34) thousand/mm3, respectively, with no statistical differences. Conclusion Newer membranes have no significant effect on platelet count. This suggests that they are, in fact, more biocompatible than their predecessors and may explain their association with increased survival. PMID:23983482

Abandoning peracetic acid-based dialyzer reuse is associated with improved survival.

PubMed

Lacson, Eduardo; Wang, Weiling; Mooney, Ann; Ofsthun, Norma; Lazarus, J Michael; Hakim, Raymond M

2011-02-01

Higher mortality risk reported with reuse versus single use of dialyzers is potentially related to reuse reagents that modify membrane surface characteristics and the blood-membrane interface. A key mechanism may involve stimulation of an inflammatory response. In a prospective crossover design, laboratory markers and mortality from 23 hemodialysis facilities abandoning reuse with peracetic acid mixture were tracked. C-reactive protein (CRP), white blood cell (WBC) count, albumin, and prealbumin were measured for 2 consecutive months before abandoning reuse and subsequently within 3 and 6 months on single use. Survival models were utilized to compare the 6-month period before abandoning reuse (baseline) and the 6-month period on single use of dialyzers after a 3-month "washout period." Patients from baseline and single-use periods had a mean age of approximately 63 years; 44% were female, 54% were diabetic, 60% were white, and the mean vintage was approximately 3.2 years. The unadjusted hazard ratio for death was 0.70 and after case-mix adjustment was 0.74 for single use compared with reuse. Patients with CRP≥5 mg/L during reuse (mean CRP=26.6 mg/ml in April) declined on single use to 20.2 mg/L by August and 20.4 mg/L by November. WBC count declined slightly during single use, but nutritional markers were unchanged. Abandonment of peracetic-acid-based reuse was associated with improved survival and lower levels of inflammatory but not nutritional markers. Further study is needed to evaluate a potential link between dialyzer reuse, inflammation, and mortality.

Dialyzer Reuse with Peracetic Acid Does Not Impact Patient Mortality

PubMed Central

Bond, T. Christopher; Krishnan, Mahesh; Wilson, Steven M.; Mayne, Tracy

2011-01-01

Summary Background and objectives Numerous studies have shown the overall benefits of dialysis filter reuse, including superior biocompatibility and decreased nonbiodegradable medical waste generation, without increased risk of mortality. A recent study reported that dialyzer reprocessing was associated with decreased patient survival; however, it did not control for sources of potential confounding. We sought to determine the effect of dialyzer reprocessing with peracetic acid on patient mortality using contemporary outcomes data and rigorous analytical techniques. Design, setting, participants, & measurements We conducted a series of analyses of hemodialysis patients examining the effects of reuse on mortality using three techniques to control for potential confounding: instrumental variables, propensity-score matching, and time-dependent survival analysis. Results In the instrumental variables analysis, patients at high reuse centers had 16.2 versus 15.9 deaths/100 patient-years in nonreuse centers. In the propensity-score matched analysis, patients with reuse had a lower death rate per 100 patient-years than those without reuse (15.2 versus 15.5). The risk ratios for the time-dependent survival analyses were 0.993 (per percent of sessions with reuse) and 0.995 (per unit of last reuse), respectively. Over the study period, 13.8 million dialyzers were saved, representing 10,000 metric tons of medical waste. Conclusions Despite the large sample size, powered to detect miniscule effects, neither the instrumental variables nor propensity-matched analyses were statistically significant. The time-dependent survival analysis showed a protective effect of reuse. These data are consistent with the preponderance of evidence showing reuse limits medical waste generation without negatively affecting clinical outcomes. PMID:21566107

Formulation and in vitro assessment of minoxidil niosomes for enhanced skin delivery.

PubMed

Balakrishnan, Prabagar; Shanmugam, Srinivasan; Lee, Won Seok; Lee, Won Mo; Kim, Jong Oh; Oh, Dong Hoon; Kim, Dae-Duk; Kim, Jung Sun; Yoo, Bong Kyu; Choi, Han-Gon; Woo, Jong Soo; Yong, Chul Soon

2009-07-30

Niosomes have been reported as a possible approach to improve the low skin penetration and bioavailability characteristics shown by conventional topical vehicle for minoxidil. Niosomes formed from polyoxyethylene alkyl ethers (Brij) or sorbitan monoesters (Span) with cholesterol molar ratios of 0, 1 and 1.5 were prepared with varying drug amount 20-50mg using thin film-hydration method. The prepared systems were characterized for entrapment efficiency, particle size, zeta potential and stability. Skin permeation studies were performed using static vertical diffusion Franz cells and hairless mouse skin treated with either niosomes, control minoxidil solution (propylene glycol-water-ethanol at 20:30:50, v/v/v) or a leading topical minoxidil commercial formulation (Minoxyl). The results showed that the type of surfactant, cholesterol and incorporated amount of drug altered the entrapment efficiency of niosomes. Higher entrapment efficiency was obtained with the niosomes prepared from Span 60 and cholesterol at 1:1 molar ratio using 25mg drug. Niosomal formulations have shown a fairly high retention of minoxidil inside the vesicles (80%) at refrigerated temperature up to a period of 3 months. It was observed that both dialyzed and non-dialyzed niosomal formulations (1.03+/-0.18 to 19.41+/-4.04%) enhanced the percentage of dose accumulated in the skin compared to commercial and control formulations (0.11+/-0.03 to 0.48+/-0.17%) except dialyzed Span 60 niosomes. The greatest skin accumulation was always obtained with non-dialyzed vesicular formulations. Our results suggest that these niosomal formulations could constitute a promising approach for the topical delivery of minoxidil in hair loss treatment.

[Is cancer incidence different between type 2 diabetes patients compared to non-diabetics in hemodialysis? A study from the REIN registry].

PubMed

Le Guillou, Aurélie; Pladys, Adelaide; Kihal, Wahida; Siebert, Muriel; Haddj-Elmrabet, Atman; Cernon, Charlotte; Bernard, Anne; Charasse, Christophe; Mandart, Lise; Hamel, Didier; Tanquerel, Tugdual; Strullu, Bernard; Richer, Christine; Siohan, Pascale; Sawadogo, Théophile; Baleynaud, Juliette; Baluta, Simona; Bayat, Sahar; Vigneau, Cécile

2018-05-01

In France, diabetes mellitus is now the second cause of end stage renal disease. In a large previous French national study, we observed that dialyzed diabetics have a significant lower risk of death by cancer. This first study was focused on cancer death but did not investigate cancer incidence. In this context, the aim of this second study was to compare the incidence of cancer in diabetic dialyzed patients compared to non-diabetic dialyzed patients in a French region. This epidemiologic multicentric study included 588 diabetic and non-diabetic patients starting hemodialysis between 2002 and 2007 in Bretagne. Data were issued from REIN registry and cancer incidence were individually collected from medical records. Diabetics and non-diabetics were matched one by one on age, sex and year of dialysis initiation. During the follow-up, we observed 28 cancers (9.4%) in diabetic patients and 26 cancers (8.9%) in non-diabetics patients. The cumulative incidence to develop a cancer 2 years after the dialysis start was approximately 6% in both diabetics and non-diabetics patients. In univariate Fine and Gray analysis, BMI, hemoglobin, statin use had P-value<0.2. However, in the adjusted model, these variables were not significantly associated with cancer incidence. This study lead on a little number of dialyzed patients did not show any significant difference on cancer incidence between diabetic and non-diabetic patients after hemodialysis start. Copyright © 2017 Société francophone de néphrologie, dialyse et transplantation. Published by Elsevier Masson SAS. All rights reserved.

Glycoxidation and inflammatory markers in patients on treatment with PMMA-based protein-leaking dialyzers.

PubMed

Galli, Francesco; Benedetti, Serena; Floridi, Ardesio; Canestrari, Franco; Piroddi, Marta; Buoncristiani, Emanuela; Buoncristiani, Umberto

2005-02-01

High-molecular-weight solutes such as glycation and oxidation protein products are putative proinflammatory mediators found in the uremic blood. The elimination of these and other large solutes by protein-leaking dialyzers (PLD) might help to correct the inflammatory status of maintenance hemodialysis (HD) patients. Two matched groups of 13 standard 3 times/week HD patients were treated for 6 months with PMMA-based PLD and non-protein-leaking dialyzers (NPLD), respectively. At baseline, 1, 3, and 6 months, we measured the blood levels of the inflammatory cytokines IL-1beta, TNF-alpha, IL-6, the acute-phase protein C-reactive protein (CRP), the adhesion molecules ICAM-1, VCAM-1, and selectine-E, the chemotaxis factors MCP-1, and the glycation and oxidation protein end products pentosidine, protein carbonyls, and AOPP. In all the patients at baseline, pre-HD levels of glycation and oxidation protein markers, and inflammatory parameters were significantly higher than in healthy control subjects (P < 0.01 or greater). After 6 months, in the group on treatment with PLD, but not in that on NPLD, there was a significant decrease (P < 0.05 or greater) of pre-HD values of total pentosidine (mainly represented by pentosidine in serum albumin; -43%), protein carbonyls (-42%), AOPP (-38%), and the inflammatory cytokines IL-1beta (-49%), IL-6 (-39%), and TNF-alpha (-20%), while IL-10 and INF-gamma increased by 67% and 37%, respectively. Proinflammatory cytokines, and particularly IL-6, showed a positive correlation with the levels of circulating pentosidine. Protidemia was not significantly modified at the end of the study in both the groups. The results in this pilot study show that the removal of large solutes by PLD can improve some indices of chronic inflammation in HD patients. Further studies are required to determine the relevance of the individual solutes removed with PLD as proinflammatory mediators in the uremic environment.

Use of a polysulfone hemodialysis membrane may prevent recurrent posterior reversible encephalopathy syndrome in a patient undergoing hemodialysis.

PubMed

Mima, Akira; Matsubara, Takeshi; Endo, Shuichiro; Murakami, Taichi; Hashimoto, Yasuki

2014-01-01

A 71-year-old woman underwent hemodialysis (HD) treatment for chronic kidney disease. During HD, she developed headache, abnormalities in visual perception, and generalized convulsion. Brain magnetic resonance imaging (MRI) showed T2-hyperintensity lesions in the posterior lobe, and an electroencephalogram showed slow waves in all areas. Twenty days later, the T2-hyperintensity lesions had vanished. Furthermore, perfusion computed tomography (CT) and single-photon emission CT with N-isopropyl[(123)I]-p-iodoamphetamine (IMP-SPECT) showed no significant abnormalities. The patient was diagnosed with posterior reversible encephalopathy syndrome (PRES) because she displayed typical clinical symptoms and MRI findings. Although several antihypertensive and antiseizure medications were administered, the patient experienced recurrent PRES. Therefore, we used a polysulfone dialyzer to reduce the oxidative stress and inflammation while preserving vascular endothelial function. After use of a polysulfone dialyzer membrane, the patient had no PRES episodes during the clinical course. This is the first study to demonstrate that use of a polysulfone dialyzer membrane instead of a cellulose membrane may prevent recurrent PRES.

Dialyzer performance in the clinic: comparison of six low-flux membranes.

PubMed

Kerr, P G; Lo, A; Chin, M m; Atkins, R C

1999-09-01

The aim of this study is to assess the clinical performance of 6 different low-flux dialysis membranes under steady-state conditions in terms of urea and phosphate clearances. Ten stable hemodialysis patients were examined. The following dialyzers were studied, all in 1.5- to 1.6-m2 format: cuprammonium, cellulose acetate, cellulose diacetate, hemophane, polysulfone (low-flux), and polysynthane. The following parameters were examined: urea reduction ratio, phosphate reduction ratio, "instantaneous dialyzer clearance" for urea and phosphate, and total amount of urea and phosphate removed in the dialysate over a 1-week (three dialyses) period. Although there were differences between the membranes, all produced results within a narrow range. There was no one membrane that produced superior clearances in all categories. The cellulose acetate membrane was the least satisfactory membrane. Phosphate clearances were at best one third that of urea clearances. When choosing a low-flux dialysis membrane, urea and phosphate clearances are so similar amongst different membranes that other criteria are likely to have a greater influence on the choice of membrane.

Catalase activity of IgG antibodies from the sera of healthy donors and patients with schizophrenia

PubMed Central

Ermakov, Evgeny A.; Smirnova, Ludmila P.; Bokhan, Nikolay A.; Semke, Arkadiy V.; Ivanova, Svetlana A.; Buneva, Valentina N.

2017-01-01

We present first evidence showing that some electrophoretically homogeneous IgGs from the sera of patients with schizophrenia (36.4%) and their Fab and F(ab)2 fragments as well as from healthy donors (33.3%) possess catalase activity. The relative catalase activity of IgGs from the sera of individual schizophrenia patients (and healthy donors) significantly varied from patient to patient, but the activity of IgGs from healthy donors is on average 15.8-fold lower than that for schizophrenia patients. After extensive dialysis of purified IgGs against EDTA chelating metal ions, the relative catalase activity of IgGs decreases on average approximately 2.5–3.7-fold; all IgGs possess metal-dependent and independent catalase activity. The addition of external Me2+ ions to dialyzed and non-dialyzed IgGs leads to a significant increase in their activity. The best activator of dialyzed and non-dialyzed IgGs is Co2+, the activation by Cu2+, Mn2+, and Ni2+ ions were rare and always lower than by Co2+. Every IgG preparation demonstrates several individual sets of very well expressed pH optima in the pH range from 4.0 to 9.5. These data speak for the individual repertoire of catalase IgGs in every person and an extreme diversity of abzymes in their pH optima and activation by different metal ions. It is known that antioxidant enzymes such as superoxide dismutases, catalases, and glutathione peroxidases represent critical defense mechanisms preventing oxidative modifications of DNA, proteins, and lipids. Catalase activity of human IgGs could probably also play a major role in the protection of organisms from oxidative stress and toxic compounds. PMID:28945759

Catalase activity of IgG antibodies from the sera of healthy donors and patients with schizophrenia.

PubMed

Ermakov, Evgeny A; Smirnova, Ludmila P; Bokhan, Nikolay A; Semke, Arkadiy V; Ivanova, Svetlana A; Buneva, Valentina N; Nevinsky, Georgy A

2017-01-01

We present first evidence showing that some electrophoretically homogeneous IgGs from the sera of patients with schizophrenia (36.4%) and their Fab and F(ab)2 fragments as well as from healthy donors (33.3%) possess catalase activity. The relative catalase activity of IgGs from the sera of individual schizophrenia patients (and healthy donors) significantly varied from patient to patient, but the activity of IgGs from healthy donors is on average 15.8-fold lower than that for schizophrenia patients. After extensive dialysis of purified IgGs against EDTA chelating metal ions, the relative catalase activity of IgGs decreases on average approximately 2.5-3.7-fold; all IgGs possess metal-dependent and independent catalase activity. The addition of external Me2+ ions to dialyzed and non-dialyzed IgGs leads to a significant increase in their activity. The best activator of dialyzed and non-dialyzed IgGs is Co2+, the activation by Cu2+, Mn2+, and Ni2+ ions were rare and always lower than by Co2+. Every IgG preparation demonstrates several individual sets of very well expressed pH optima in the pH range from 4.0 to 9.5. These data speak for the individual repertoire of catalase IgGs in every person and an extreme diversity of abzymes in their pH optima and activation by different metal ions. It is known that antioxidant enzymes such as superoxide dismutases, catalases, and glutathione peroxidases represent critical defense mechanisms preventing oxidative modifications of DNA, proteins, and lipids. Catalase activity of human IgGs could probably also play a major role in the protection of organisms from oxidative stress and toxic compounds.

Corneal Endothelial Alterations in Chronic Renal Failure.

PubMed

Sati, Alok; Jha, Ashok; Moulick, P S; Shankar, Sandeep; Gupta, Sandeep; Khan, M A; Dogra, Manu; Sangwan, Virender S

2016-10-01

To evaluate the corneal endothelial changes in patients with chronic renal failure. A total of 128 corneas of 128 subjects were studied, and 3 groups were formed. The first, the dialyzed group, composed of 32 corneas of 32 patients; the second, the nondialyzed group, composed of 34 corneas of 34 patients; and the third, the age-matched control group, composed of 64 corneas of 64 healthy subjects were examined by a specular microscope and the endothelial parameters were compared. The dialyzed group (enhanced level of toxins in the blood) was further analyzed to assess the influence of blood urea, serum creatinine, serum calcium, and serum phosphorus including the duration of dialysis on corneal endothelium. On comparing the 3 groups using analysis of variance and posthoc tests, a significant difference was found in the central corneal thickness (CCT) and endothelial cell density (CD) between the control (CCT: 506 ± 29 μm, CD: 2760 ± 304 cells/mm) and dialyzed groups (CCT: 549 ± 30 μm, CD: 2337 ± 324 cells/mm) [P < 0.001 (CCT); P < 0.001 (CD)]; control and nondialyzed groups (CCT: 524 ± 27 μm, CD: 2574 ± 260 cells/mm) [P = 0.023 (CCT); P = 0.016 (CD)]; and dialyzed and nondialyzed groups [P = 0.002 (CCT); P = 0.007 (CD)]. Using the linear generalized model, a significant correlation was found between the endothelial parameters and blood urea only [P = 0.006 (CCT), 0.002 (coefficient of variation), 0.022 (CD), and 0.026 (percentage of hexagonality)], although the correlation was poorly positive for CCT but poorly negative for the remaining endothelial parameters. Corneal endothelial alteration is present in patients with chronic renal failure, more marked in patients undergoing hemodialysis and with raised blood urea level.

Abandoning Peracetic Acid-Based Dialyzer Reuse Is Associated with Improved Survival

PubMed Central

Wang, Weiling; Mooney, Ann; Ofsthun, Norma; Lazarus, J. Michael; Hakim, Raymond M.

2011-01-01

Summary Background and objectives Higher mortality risk reported with reuse versus single use of dialyzers is potentially related to reuse reagents that modify membrane surface characteristics and the blood-membrane interface. A key mechanism may involve stimulation of an inflammatory response. Design, setting, participants, & measurements In a prospective crossover design, laboratory markers and mortality from 23 hemodialysis facilities abandoning reuse with peracetic acid mixture were tracked. C-reactive protein (CRP), white blood cell (WBC) count, albumin, and prealbumin were measured for 2 consecutive months before abandoning reuse and subsequently within 3 and 6 months on single use. Survival models were utilized to compare the 6-month period before abandoning reuse (baseline) and the 6-month period on single use of dialyzers after a 3-month “washout period.” Results Patients from baseline and single-use periods had a mean age of approximately 63 years; 44% were female, 54% were diabetic, 60% were white, and the mean vintage was approximately 3.2 years. The unadjusted hazard ratio for death was 0.70 and after case-mix adjustment was 0.74 for single use compared with reuse. Patients with CRP ≥ 5 mg/L during reuse (mean CRP = 26.6 mg/ml in April) declined on single use to 20.2 mg/L by August and 20.4 mg/L by November. WBC count declined slightly during single use, but nutritional markers were unchanged. Conclusions Abandonment of peracetic-acid-based reuse was associated with improved survival and lower levels of inflammatory but not nutritional markers. Further study is needed to evaluate a potential link between dialyzer reuse, inflammation, and mortality. PMID:20947788

The Effect of Dialysis Chains on Mortality among Patients Receiving Hemodialysis

PubMed Central

Zhang, Yi; Cotter, Dennis J; Thamer, Mae

2011-01-01

Objective To examine the association between dialysis facility chain affiliation and patient mortality. Study Setting Medicare dialysis population. Study Design Data from the United States Renal Data System (USRDS) were used to identify 3,601 free-standing dialysis facilities and 34,914 Medicare patients' incidence to end-stage renal disease (ESRD) in 2004. Mixed-effect regression models were used to estimate patient mortality by dialysis facility chain and profit status during the 2-year follow-up. Data Collection USRDS data were matched with facility, cost, and census data. Principle Findings Of the five largest dialysis chains, the lowest mortality risk was observed among patients dialyzed at nonprofit (NP) Chain 5 facilities. Compared with Chain 5, hazard ratios were 19 percent higher (95 percent CI 1.06–1.34) and 24 percent higher (95 percent CI 1.10–1.40) for patients dialyzed at for-profit (FP) Chain 1 and Chain 2 facilities, respectively. In addition, patients at FP facilities had a 13 percent higher risk of mortality than those in NP facilities (95 percent CI 1.06–1.22). Conclusions Large chain affiliation is an independent risk factor for ESRD mortality in the United States. Given the movement toward further consolidation of large FP chains, reasons behind the increase in mortality require scrutiny. PMID:21143480

Transfer of endogenous pyrogens across artificial membranes?

PubMed

Lonnemann, G; Linnenweber, S; Burg, M; Koch, K M

1998-05-01

Synthetic high-flux dialyzer membranes used in continuous veno-venous hemofiltration are permeable to middle molecular size endogenous pyrogens, the pro-inflammatory cytokines IL-1 beta and TNF-alpha. The quantities removed by sieving are, however, negligible in vitro as well as in vivo. Adsorption of cytokines to the membrane polymer is the major mechanism of pyrogen removal. Adsorption seems to be semispecific for pro-inflammatory cytokines because levels of anti-inflammatory mediators were not changed or even increased during CVVH. Thus, CVVH may change cytokine profiles in septic patients supporting the predominance of anti-inflammatory over pro-inflammatory activity in plasma. It remains to be demonstrated whether modifications of extracorporeal blood purification systems (high-volume CVVH, plasma separation + adsorption) are able to amplify the change in cytokine profiles and whether this change influences outcome of septic patients.

Nucleic acid isolation

DOEpatents

Longmire, J.L.; Lewis, A.K.; Hildebrand, C.E.

1988-01-21

A method is provided for isolating DNA from eukaryotic cell and flow sorted chromosomes. When DNA is removed from chromosome and cell structure, detergent and proteolytic digestion products remain with the DNA. These products can be removed with organic extraction, but the process steps associated with organic extraction reduces the size of DNA fragments available for experimental use. The present process removes the waste products by dialyzing a solution containing the DNA against a solution containing polyethylene glycol (PEG). The waste products dialyze into the PEG leaving isolated DNA. The remaining DNA has been prepared with fragments containing more than 160 kb. The isolated DNA has been used in conventional protocols without effect on the protocol.

Preparation and Preliminary Dialysis Performance Research of Polyvinylidene Fluoride Hollow Fiber Membranes

PubMed Central

Zhang, Qinglei; Lu, Xiaolong; Liu, Juanjuan; Zhao, Lihua

2015-01-01

In this study, the separation properties of Polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were improved by optimizing membrane morphology and structure. The results showed that the PVDF membrane had better mechanical and separation properties than Fresenius Polysulfone High-Flux (F60S) membrane. The PVDF membrane tensile stress at break, tensile elongation and bursting pressure were 11.3 MPa, 395% and 0.625 MPa, respectively. Ultrafiltration (UF) flux of pure water reached 108.2 L∙h−1∙m−2 and rejection of Albumin from bovine serum was 82.3%. The PVDF dialyzers were prepared by centrifugal casting. The influences of membrane area and simulate fluid flow rate on dialysis performance were investigated. The results showed that the clearance rate of urea and Lysozyme (LZM) were improved with increasing membrane area and fluid flow rate while the rejection of albumin from bovine serum (BSA) had little influence. The high-flux PVDF dialyzer UF coefficient reached 62.6 mL/h/mmHg. The PVDF dialyzer with membrane area 0.69 m2 has the highest clearance rate to LZM and urea. The clearance rate of LZM was 66.8% and urea was 87.7%. PMID:25807890

Purification and Properties of Streptococcal Competence Factor Isolated from Chemically Defined Medium

PubMed Central

Leonard, C. Gomez; Cole, Roger M.

1972-01-01

A procedure for the isolation and purification of competence factor produced in a defined medium by group H streptococci, strain Challis-6, is presented. Partial characterization and chemical analysis of the product are described. The procedure yields competence factor of high purity, as shown by homogeneity in electrofocusing, by electrophoresis in sodium dodecyl sulfate polyacrylamide gels, and by chemical analysis. The data indicate that competence factor is a small, dialyzable, highly basic compound. It is free from lipids, phosphorus, and carbohydrates, and is colorless and thermoresistant. Its biological activity is destroyed by trypsin but not by deoxyribonuclease, ribonuclease, lipase, or lysozyme. Its high isoelectric point of above pH 11.0 suggests that competence factor may be a protamine or a polymer of basic amino acids. The possibility that a polyamine may be an integral part of the polypeptide molecule has not been excluded. PMID:5018023

Nucleic acid isolation process

DOEpatents

Longmire, Jonathan L.; Lewis, Annette K.; Hildebrand, Carl E.

1990-01-01

A method is provided for isolating DNA from eukaryotic cell and flow sorted chromosomes. When DNA is removed from chromosome and cell structure, detergent and proteolytic digestion products remain with the DNA. These products can be removed with organic extraction, but the process steps associated with organic extraction reduce the size of DNA fragments available for experimental use. The present process removes the waste products by dialyzing a solution containing the DNA against a solution containing polyethylene glycol (PEG). The waste products dialyze into the PEG leaving isolated DNA. The remaining DNA has been prepared with fragments containing more than 160 kb. The isolated DNA has been used in conventional protocols without affect on the protocol.

Effect of beef broth protein on the thermal inactivation of staphylococcal enterotoxin B1.

PubMed Central

Lee, I C; Stevenson, K E; Harmon, L G

1977-01-01

Enterotoxin B produced by Staphylococus aureus 243 in brain heart infusion broth was concentrated by dialysis against 40% polyethylene glycol (20 M), partially purified on a Sephadex G-100 column and heated at 110 degrees C in thermal death time cans. Various heating menstrua included 0.04 M Veronal buffer (pH 7.4), beef broth, and fractions of beef broth obtained by ultrafiltration or precipitation with ammonium sulfate. The toxin was assayed serologically using the microslide gel double-diffusion method. The time requiring for 90% inactivation at 110 degrees C (D110 value) obtained in buffer and in beef broth was 18 and 60 min, respectively. When the concentration of beef broth was increased fivefold, the D110 increased to 78 min. The apparent protective effect or protein was further investigated using beef broth protein obtained by precipitation with (NH4)2SO4. The D110 values were 51 and 70 min when the protein concentration in the heating menstruum was 3.8 and 7.7 mg/ml, respectively. However, when the beef broth protein was dialyzed against buffer before use as a heating menstrum, the D110 was only 39 or 41 min at comparable protein concentrations. Results indicated a dialyzable factor, whose protective effect was partially destroyed by trypsin and chymotrypsin but did not by disodium ethylenediaminetetraacetate, was involved in the protection of enterotoxin B during heating. PMID:403860

[Unconventional hemodiafiltration: double-high-flux and push-pull].

PubMed

Lentini, Paolo; Pellanda, Valentina; Contestabile, Andrea; Berlingo, Graziella; de Cal, Massimo; Ronco, Claudio; Dell'Aquila, Roberto

2012-01-01

Growing evidence demonstrates that morbidity and mortality in patients with end-stage renal disease correlate significantly with retention of larger uremic toxins including β2 microglobulin. Even when hemodialysis is performed, complications such as dialysis-associated amyloidosis are likely to develop. These complications seem to be related to the retention and accumulation of larger uremic substances, only a small amount of which are removed by hemodialysis. On-line hemodiafiltration (OL-HDF) is popular but expensive; double-highflux hemodiafiltration (DHF-HDF) and push-pull hemodiafiltration (PP-HDF), special types of HDF, are very efficient treatments without the need for ultrapure substitution fluid. In DHF-HDF two high-flux dialyzers are connected in series by blood and dialysate lines. In the first dialyzer mixed diffusion convection removes fluid and solutes; in the second dialyzer backfiltration of sterile dialysate occurs, resembling the post-dilution OL-HDF mode. The PP-HDF method alternates rapid convection of body fluids and rapid backfiltration of sterile pyrogen-free dialysate using a high-flux membrane and a double-pump system. These treatments require an elevated blood flow and have the advantage that they use dialysis fluid instead of ultrapure fluid. Several studies have shown an elevated removal rate of middle molecules and reduction of dialysis-related amyloidosis symptoms like back and shoulder pain, restless leg syndrome, and carpal tunnel syndrome.

Enhanced H-filter based on Fåhræus-Lindqvist effect for efficient and robust dialysis without membrane

PubMed Central

Zheng, Wei-Chao; Xie, Rui; He, Li-Qun; Xi, Yue-Heng; Liu, Ying-Mei; Meng, Zhi-Jun; Wang, Wei; Ju, Xiao-Jie; Chen, Gang; Chu, Liang-Yin

2015-01-01

A novel microfluidic device for highly efficient and robust dialysis without membrane is highly desired for the development of portable or wearable microdialyzer. Here we report an enhanced H-filter with pillar array based on Fåhræus-Lindqvist effect (F-L effect) for highly efficient and robust membraneless dialysis of simplified blood for the first time. The H-filter employs two fluids laminarly flowing in the microchannel for continuously membraneless dialysis. With pillar array in the microchannel, the two laminar flows, with one containing blood cells and small molecules and another containing dialyzate solution, can form a cell-free layer at the interface as selective zones for separation. This provides enhanced mixing yet extremely low shear for extraction of small molecules from the blood-cell-containing flow into the dialyzate flow, resulting in robust separation with reduced cell loss and improved efficiency. We demonstrate this by first using Chlorella pyrenoidosa as model cells to quantitatively study the separation performances, and then using simplified human blood for dialysis. The advanced H-filter, with highly efficient and robust performance for membraneless dialysis, shows great potential as promising candidate for rapid blood analysis/separation, and as fundamental structure for portable dialyzer. PMID:26339313

Effect of membrane flux and dialyzer biocompatibility on survival in end-stage diabetic nephropathy.

PubMed

Götz, Angela K; Böger, Carsten A; Popal, Massoud; Banas, Bernhard; Krämer, Bernhard K

2008-01-01

We examined the effects of dialyzer membrane flux and biocompatibility on mortality in diabetic dialysis patients. We enrolled 402 prevalent chronic hemodialysis patients from 30 centers in Germany in 1999 for a prospective observational study until 2003. We compared 2 groups in post hoc analysis: high-flux (HF, n = 166) versus low-flux (LF, n = 236) membrane, and high biocompatibility (HB, n = 300) versus low biocompatibility (LB, n = 102). All-cause mortality (ACM) was the primary endpoint. Death causes were the secondary endpoints. Multivariate Cox regression analysis showed no significant difference in risk for ACM with respect to flux (hazard ratio, HR, 0.79; p = 0.08; ACM 63% in HF vs. 70% in LF dialysis) and biocompatibility level (HR 1.00; p = 0.98; ACM 67% for HB vs. 66% for LB). The multivariate analysis of different causes of death did not reveal any outcome differences dependent on flux and biocompatibility level apart from a slightly better cumulative survival regarding the death cause 'infectious' in our HF dialysis group (HR 0.48; p = 0.07, Kaplan-Meier analysis p = 0.03). Our data indicate that mortality of hemodialysis patients with type-2 diabetic nephropathy is influenced neither by dialyzer flux level nor by biocompatibility. Copyright 2008 S. Karger AG, Basel.

Enhanced H-filter based on Fåhræus-Lindqvist effect for efficient and robust dialysis without membrane.

PubMed

Zheng, Wei-Chao; Xie, Rui; He, Li-Qun; Xi, Yue-Heng; Liu, Ying-Mei; Meng, Zhi-Jun; Wang, Wei; Ju, Xiao-Jie; Chen, Gang; Chu, Liang-Yin

2015-07-01

A novel microfluidic device for highly efficient and robust dialysis without membrane is highly desired for the development of portable or wearable microdialyzer. Here we report an enhanced H-filter with pillar array based on Fåhræus-Lindqvist effect (F-L effect) for highly efficient and robust membraneless dialysis of simplified blood for the first time. The H-filter employs two fluids laminarly flowing in the microchannel for continuously membraneless dialysis. With pillar array in the microchannel, the two laminar flows, with one containing blood cells and small molecules and another containing dialyzate solution, can form a cell-free layer at the interface as selective zones for separation. This provides enhanced mixing yet extremely low shear for extraction of small molecules from the blood-cell-containing flow into the dialyzate flow, resulting in robust separation with reduced cell loss and improved efficiency. We demonstrate this by first using Chlorella pyrenoidosa as model cells to quantitatively study the separation performances, and then using simplified human blood for dialysis. The advanced H-filter, with highly efficient and robust performance for membraneless dialysis, shows great potential as promising candidate for rapid blood analysis/separation, and as fundamental structure for portable dialyzer.

Fluctuation of Ultrafiltration Coefficient of Hemodialysis Membrane During Reuse

NASA Astrophysics Data System (ADS)

Arif, Idam; Christin

2010-12-01

Hemodialysis treatment for patient with kidney failure is to regulate body fluid and to excrete waste products of metabolism. The patient blood and the dialyzing solution (dialysate) are flowed counter currently in a dialyzer to allow volume flux of fluid and diffusion of solutes from the blood to the dialysate through a semipermiable membrane. The volume flux of fluid depends on the hydrostatic and the osmotic pressure difference between the blood and the dialysate. It also depends on the membrane parameter that represents how the membrane allows the fluid and the solutes to move across as a result of the pressure difference, known as the ultrafiltration coefficient Kuf. The coefficient depends on the number and the radius of membrane pores for the movement of the fluids and the solutes across the membrane. The measured membrane ultrafiltration coefficient of reused dialyzer shows fluctuation between one uses to another without any significant trend of change. This indicates that the cleaning process carried out before reuse does not cause perfect removal of clots that happen in the previous use. Therefore the unblocked pores are forced to work hardly to obtain targeted volume flux in a certain time of treatment. This may increase the unblocked pore radius. Reuse is stopped when there is indication of blood leakage during the hemodialysis treatment.

Finite Volume Scheme for Double Convection-Diffusion Exchange of Solutes in Bicarbonate High-Flux Hollow-Fiber Dialyzer Therapy

PubMed Central

Annan, Kodwo

2012-01-01

The efficiency of a high-flux dialyzer in terms of buffering and toxic solute removal largely depends on the ability to use convection-diffusion mechanism inside the membrane. A two-dimensional transient convection-diffusion model coupled with acid-base correction term was developed. A finite volume technique was used to discretize the model and to numerically simulate it using MATLAB software tool. We observed that small solute concentration gradients peaked and were large enough to activate solute diffusion process in the membrane. While CO2 concentration gradients diminished from their maxima and shifted toward the end of the membrane, HCO3 − concentration gradients peaked at the same position. Also, CO2 concentration decreased rapidly within the first 47 minutes while optimal HCO3 − concentration was achieved within 30 minutes of the therapy. Abnormally high diffusion fluxes were observed near the blood-membrane interface that increased diffusion driving force and enhanced the overall diffusive process. While convective flux dominated total flux during the dialysis session, there was a continuous interference between convection and diffusion fluxes that call for the need to seek minimal interference between these two mechanisms. This is critical for the effective design and operation of high-flux dialyzers. PMID:23197994

Rationale and design of the HepZero study: a prospective, multicenter, international, open, randomized, controlled clinical study with parallel groups comparing heparin-free dialysis with heparin-coated dialysis membrane (Evodial) versus standard care: study protocol for a randomized controlled trial.

PubMed

Rossignol, Patrick; Dorval, Marc; Fay, Renaud; Ros, Joan Fort; Loughraieb, Nathalie; Moureau, Frédérique; Laville, Maurice

2013-06-01

Anticoagulation for chronic dialysis patients with contraindications to heparin administration is challenging. Current guidelines state that in patients with increased bleeding risks, strategies that can induce systemic anticoagulation should be avoided. Heparin-free dialysis using intermittent saline flushes is widely adopted as the method of choice for patients at risk of bleeding, although on-line blood predilution may also be used. A new dialyzer, Evodial (Gambro, Lund, Sweden), is grafted with unfractionated heparin during the manufacturing process and may allow safe and efficient heparin-free hemodialysis sessions. In the present trial, Evodial was compared to standard care with either saline flushes or blood predilution. The HepZero study is the first international (seven countries), multicenter (10 centers), randomized, controlled, open-label, non-inferiority (and if applicable subsequently, superiority) trial with two parallel groups, comprising 252 end-stage renal disease patients treated by maintenance hemodialysis for at least 3 months and requiring heparin-free dialysis treatments. Patients will be treated during a maximum of three heparin-free dialysis treatments with either saline flushes or blood predilution (control group), or Evodial. The first heparin-free dialysis treatment will be considered successful when there is: no complete occlusion of air traps or dialyzer rendering dialysis impossible; no additional saline flushes to prevent clotting; no change of dialyzer or blood lines because of clotting; and no premature termination (early rinse-back) because of clotting.The primary objectives of the study are to determine the effectiveness of the Evodial dialyzer, compared with standard care in terms of successful treatments during the first heparin-free dialysis. If the non-inferiority of Evodial is demonstrated then the superiority of Evodial over standard care will be tested. The HepZero study results may have major clinical implications for patient care. ClinicalTrials.gov NCT01318486.

[Prevalence of histological types of bone disease in a hemodialysis center limiting the oral intake of aluminum hydroxide].

PubMed

Belbrik, S; Marie, A; Boudailliez, B; Morinière, P; Sébert, J L; Solal, M C; Westeel, P F; Roche, D; Fournier, A

1990-01-01

To assess the prevalence of histologic bone disease in our center where Al(OH)3 intake is restricted, we reviewed 42 bone biopsies performed between 1975 and 1985 in patients dialyzed more than 29 months. Bone biopsies were performed systematically (2/3 of the cases) or because of a mild hypercalcemia (1/3 of the cases). Seventeen of these patients had been dialyzed before 1978 with softened water moderately contaminated by aluminum. Fifteen had always been dialyzed with reverse osmosis treated water and 10 had been exclusively treated by hemofiltration. The prevalence of osteitis fibrosa was 76%, that of osteomalacia null and that of adynamic bone disease 24% (but only 9.5% with positive Aluminon staining). When the 17 patients dialyzed with aluminum contaminated water before 1978 were excluded, only one patient among 25 had an aluminum adynamic bone disease (4%). This low prevalence can probably be explained by the restricted intake of Al(OH)3 thanks to the systematic administration of Ca CO3 and in a few cases of Mg (OH). The adynamic bone disease group has lower serum concentration of PTH and shorter duration on dialysis whereas the serum levels of calcium, phosphorus, magnesium and aluminum and daily dose of Ca CO3, Mg (OH)2 and Al(OH)3 do not differ. The frequency of the positivity of aluminum staining is not statistically different in the 2 groups. In 4 cases, adynamic bone disease without aluminum or iron intoxications is found, associated with a relative hypoparathyroidism. It is not explained by previous parathyroidectomy, diabetes or steroid therapy. 1) Restriction of aluminum intake and dialysis with reverse osmosis treated water lead to a low prevalence of aluminum bone disease. 2) A new bone disease in uremia is described: the idiopathic adynamic bone disease associated with a relative hypoparathyroidism.

Toward the treatment for Alzheimer's disease: adsorption is primary mechanism of removing amyloid β protein with hollow-fiber dialyzers of the suitable materials, polysulfone and polymethyl methacrylate.

PubMed

Kawaguchi, Kazunori; Saigusa, Akira; Yamada, Shinji; Gotoh, Takehiro; Nakai, Shigeru; Hiki, Yoshiyuki; Hasegawa, Midori; Yuzawa, Yukio; Kitaguchi, Nobuya

2016-06-01

The accumulation of amyloid β protein (Aβ) in the brain reflects cognitive impairment in Alzheimer's disease. We hypothesized that the rapid removal of Aβ from the blood by an extracorporeal system may act as a peripheral Aβ sink from the brain. The present study aimed to determine the optimal materials and modality for Aβ removal by hemodialyzers. In a batch analysis, hollow-fiber fragments of polysulfone (PSf) and polymethyl methacrylate (PMMA) showed greater removal efficiency of Aβ than did other materials, such as cellulose-triacetates and ethylene-vinyl alcohol copolymer (PSf:PMMA at 30 min, 98.6 ± 2.4 %:97.8 ± 0.4 % for Aβ1-40 and 96.6 ± 0.3 %:99.0 ± 1.0 % for Aβ1-42). In a modality study, the Aβ solution was applied to PSf dialyzers and circulated in the dialysis and Air-filled adsorption-mode (i.e., the outer space of the hollow fibers was filled with air) or phosphate-buffered saline (PBS)-filled adsorption modes. The Aβ1-40 removal efficiency of the pre/post dialyzer in the Air-filled adsorption-mode was the highest (62.4 ± 12.6 %, p = 0.007). In a flow rate study in the Air-filled adsorption-mode, 200 mL/min showed the highest Aβ1-40 reduction rate of pool solution (97.3 ± 0.8 % at 15 min) compared with 20 mL/min (p = 0.00001) and 50 mL/min (p = 0.00382). PMMA dialyzers showed similar high reduction rates. Thus, the optimal modality for Aβ removal was the adsorption-mode with PSf or PMMA hollow fibers at around 50 mL/min flow rate, which seems to be suitable for clinical use.

Molecular biology-based assessment of vitamin E-coated dialyzer effects on oxidative stress, inflammation, and vascular remodeling.

PubMed

Calò, Lorenzo A; Naso, Agostino; D'Angelo, Angela; Pagnin, Elisa; Zanardo, Marco; Puato, Massimo; Rebeschini, Mirka; Landini, Silvano; Feriani, Mariano; Perego, Angelo; Malagoli, Andrea; Zagatti, Riccardo; Calzavara, Piergianni; Cascone, Carmelo; Davis, Paul A

2011-02-01

Cardiovascular disease represents the most common cause for the excess of morbidity and mortality found in end-stage renal disease (ESRD) and has prompted the exploration of multiple approaches to improve outcomes in these patients. Cardiovascular risk factors such as increased oxidative stress (OxSt) and inflammation are found in ESRD patients. A vitamin E-coated dialyzer using polysulfone membranes has been suggested to have positive effects on these factors. This 1-year study evaluated in 25 ESRD patients under chronic dialysis, the effects of a vitamin E-coated membrane (VitabranE ViE) "ex vivo" on mononuclear cells, OxSt, and inflammation-related biochemical and molecular biology markers using a molecular biology approach. p22(phox), heme oxygenase (HO)-1, plasminogen activator inhibitor (PAI)-1 protein level, and phosphorylated extracellular signal-regulated kinase (pERK)1/2 status were evaluated at the beginning of the study, after 6 months and after 12 months by Western blot analysis and oxidized low-density lipoprotein (OxLDL) plasma level by enzyme-linked immunosorbent assay, alongside vascular remodeling assessment as measured by carotid intima-media thickness (IMT) in a subgroup of nine randomly selected patients. p22(phox), PAI-1, OxLDL, and pERK all decreased with VitabranE use, while HO-1 increased. Carotid IMT did not increase. Treatment with VitabranE significantly decreases the expression of proteins and markers relevant to OxSt and inflammation tightly associated with cardiovascular disease, and it appears highly likely that VitabranE use will provide a benefit in terms of cardiovascular protection. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Can duration of hemodialysis be estimated based on the on-arrival laboratory tests and clinical manifestations in methanol-poisoned patients?

PubMed

Pajoumand, Abdolkarim; Zamani, Nasim; Hassanian-Moghaddam, Hossein; Shadnia, Shahin

2017-06-01

We aimed to evaluate the efficacy of Lachance formula and more readily available clinical or laboratory factors (other than serum methanol level) in prediction of the needed time for hemodialysis in methanol-poisoned patients. In a retrospective study, all methanol-poisoned patients referred to us between March 2008 and March 2016 were enrolled. The patients' demographic characteristics, on-arrival vital signs, signs/symptoms, and laboratory tests were evaluated for factors that could prognosticate the dialysis duration. Of 72 patients enrolled, 54 underwent hemodialysis once (group 1) and 18 needed more than one session of hemodialysis (group 2). All were treated by ethanol, bicarbonate, and leucovorin. Lachance formula overestimated the patients in higher methanol levels and underestimated them in lower methanol levels. It properly predicted the needed time for hemodialysis when the methanol level was between 15 and 25 mg/dL. Groups 1 and 2 were different in terms of their ingested alcohol dose (P = 0.001), creatinine (P = 0.02), dyspnea on presentation (P = 0.002), and the place they had been dialyzed (P = 0.013). Dialysis duration significantly correlated with dyspnea on presentation (P = 0.028) and ingested alcohol dose (P = 0.02). After performance of logistic regression analysis, only creatinine was statistically significantly different between the two groups (P = 0.02). Median creatinine levels were 1.3 [1, 6] (0.8-2.7) and 1.4 [1.35, 2.1] (0.8-6.5) in the patients who were dialyzed once and twice, respectively. As a conclusion, creatinine is possibly a readily available test that can predict the appropriate time needed for hemodialysis in methanol-poisoned patients.

Serum Soluble (Pro)Renin Receptor Levels in Maintenance Hemodialysis Patients

PubMed Central

Amari, Yoshifumi; Morimoto, Satoshi; Nakajima, Fumitaka; Ando, Takashi; Ichihara, Atsuhiro

2016-01-01

The (pro)renin receptor [(P)RR] is cleaved by furin to generate soluble (P)RR [s(P)RR], which reflects the status of the tissue renin-angiotensin system. Hemodialysis patients have advanced atherosclerosis. The aim of this study was to investigate the relationships between serum s(P)RR levels and background factors, including indices of atherosclerosis, in hemodialysis patients. Serum s(P)RR levels were measured in hemodialysis patients and clearance of s(P)RR through the membrane of the dialyzer was examined. Furthermore, relationships between serum s(P)RR levels and background factors were assessed. Serum s(P)RR levels were significantly higher in hemodialysis patients (30.4 ± 6.1 ng/ml, n = 258) than those in subjects with normal renal function (21.4 ± 6.2 ng/ml, n = 39, P < 0.0001). Clearance of s(P)RR and creatinine were 56.9 ± 33.5 and 147.6 ± 9.50 ml/min, respectively. Serum s(P)RR levels were significantly higher in those with ankle-brachial index (ABI) of < 0.9, an indicator of severe atherosclerosis, than those with ABI of ≥ 0.9 (32.2 ± 5.9 and 30.1 ± 6.2 ng/ml, respectively, P < 0.05). An association between low ABI and high serum s(P)RR levels was observed even after correction for age, history of smoking, HbA1c, and LDL-C. Serum s(P)RR levels were significantly higher in hemodialysis patients when compared with subjects with normal renal function, although s(P)RR is dialyzed to some extent, but to a lesser extent than creatinine. High serum s(P)RR levels may be associated with atherosclerosis independent of other risk factors, suggesting that serum s(P)RR could be used as a marker for atherosclerotic conditions in hemodialysis patients. PMID:27367528

Factors Affecting Hemodialysis Adequacy in Cohort of Iranian Patient with End Stage Renal Disease.

PubMed

Shahdadi, Hosein; Balouchi, Abbas; Sepehri, Zahra; Rafiemanesh, Hosein; Magbri, Awad; Keikhaie, Fereshteh; Shahakzehi, Ahmad; Sarjou, Azizullah Arbabi

2016-08-01

There are many factors that can affect dialysis adequacy; such as the type of vascular access, filter type, device used, and the dose, and rout of erythropoietin stimulation agents (ESA) used. The aim of this study was investigating factors affecting Hemodialysis adequacy in cohort of Iranian patient with end stage renal disease (ESRD). This is a cross-sectional study conducted on 133 Hemodialysis patients referred to two dialysis units in Sistan-Baluchistan province in the cities of Zabol and Iranshahr, Iran. We have looked at, (the effects of the type of vascular access, the filter type, the device used, and the dose, route of delivery, and the type of ESA used) on Hemodialysis adequacy. Dialysis adequacy was calculated using kt/v formula, two-part information questionnaire including demographic data which also including access type, filter type, device used for hemodialysis (HD), type of Eprex injection, route of administration, blood groups and hemoglobin response to ESA were utilized. The data was analyzed using the SPSS v16 statistical software. Descriptive statistical methods, Mann-Whitney statistical test, and multiple regressions were used when applicable. The range of calculated dialysis adequacy is 0.28 to 2.39 (units of adequacy of dialysis). 76.7% of patients are being dialyzed via AVF and 23.3% of patients used central venous catheters (CVC). There was no statistical significant difference between dialysis adequacy, vascular access type, device used for HD (Fresenius and B. Braun), and the filter used for HD (p> 0.05). However, a significant difference was observed between the adequacy of dialysis and Eprex injection and patients' time of dialysis (p <0.05). Subcutaneous ESA (Eprex) injection and dialysis shift (being dialyzed in the morning) can have positive impact on dialysis adequacy. Patients should be educated on the facts that the type of device used for HD and the vascular access used has no significant effects on dialysis adequacy.

Fungal Pathogen of Cladophora glomerata (Chlorophyta)

PubMed Central

Bott, Thomas L.; Rogenmuser, Kurt

1980-01-01

A strain of Acremonium kiliense (Fungi Imperfecti) produced a water-soluble, dialyzable, heat-stable agent that rendered Cladophora glomerata (Chlorophyta) chlorotic and inhibited its growth. PMID:16345663

Defective neutrophil chemotaxis in juvenile periodontitis.

PubMed Central

Clark, R A; Page, R C; Wilde, G

1977-01-01

Neutrophil chemotaxis was evaluated in nine patients with juvenile periodontitis, with normal subjects and patients with the adult form of periodontitis as controls. Defective chemotactic responses were observed in neutrophils from seven of nine juvenile patients, and a reduced level of complement-derived chemotactic activity was demonstrated in serum from four patients. These determinations were normal in all the patients with adult periodontitis. Serum from five of the juvenile patients contained a heat-stable, non-dialyzable factor that markedly inhibited the chemotaxis of normal neutrophils. Thus the characteristic tissue destruction seen in juvenile periodontitis may be, at least in part, a consequence of a failure of host defense mechanisms. PMID:591063

Analysis of a Single Hemodialysis on Phosphate Removal of the Internal Fistula Patients by Mathematical and Statistical Methods

PubMed Central

Yu, Qiyao; Bai, Yaling; Zhang, Junxia; Cui, Liwen; Zhang, Huiran; Xu, Jinsheng; Gao, Chao

2013-01-01

Chronic kidney disease related mineral and bone disease (CKD-MBD) is a worldwide challenge in hemodialysis patients. In china, the number of dialysis patients is growing but few data are available about their bone disorders. In the current study, we aimed to evaluate the effect of clinical factors on the serum phosphorus clearance in the 80 maintenance hemodialysis (MHD) patients. Six clinical factors were identified for their association with the serum phosphorus clearance using the analysis of Spearman's single linear correlation, including predialysis serum phosphate level, CRR, membrane surface area of the dialyzer, effective blood flow rate, the blood chamber volume, and hematocrit. In an overall multivariate analysis, pre-P, CRR, membrane SA, and Qb were identified as independent risk factors associated with the serum phosphorus clearance. In conclusion, HD could effectively clear serum phosphorus. The analysis of CRR might help to estimate serum phosphorus reduction ratio. PMID:24454542

Angiogenin: a novel inhibitor of neutrophil lactoferrin release during extracorporeal circulation.

PubMed

Schmaldienst, Sabine; Oberpichler, André; Tschesche, Harald; Hörl, Walter H

2003-01-01

Degranulation of polymorphonuclear leukocytes (PMNL) occurs during extracorporeal circulation. A degranulation-inhibiting protein identical to angiogenin was recently isolated from high-flux dialyzer ultrafiltrate. This protein inhibits the release of lactoferrin and metalloproteinases from PMNL in vitro. In the present study, we investigated end-stage renal disease patients undergoing regular hemodialysis treatment with either high-flux dialyzers (n = 51) or low-flux dialyzers (n = 44), and chronically uremic patients undergoing hemodiafiltration (n = 30). Hemodialysis therapy with low-flux polysulfone or cellulose triacetate membranes caused no or only minimal reduction (

Bovine and porcine heparins: different drugs with similar effects on human haemodialysis

PubMed Central

2013-01-01

Background Heparins from porcine and bovine intestinal mucosa differ in their structure and also in their effects on coagulation, thrombosis and bleeding. However, they are used as undistinguishable drugs. Methods We compared bovine and porcine intestinal heparin administered to patients undergoing a particular protocol of haemodialysis. We compared plasma concentrations of these two drugs and also evaluated how they affect patients and the dialyzer used. Results Compared with porcine heparin, bovine heparin achieved only 76% of the maximum plasma concentration as IU mL-1. This observation is consistent with the activities observed in the respective pharmaceutical preparations. When the plasma concentrations were expressed on weight basis, bovine heparin achieved a maximum concentration 1.5 fold higher than porcine heparin. The reduced anticoagulant activity and higher concentration, on weight basis, achieved in the plasma of patients under dialysis using bovine instead of porcine heparin did not affect significantly the patients or the dialyzer used. The heparin dose is still in a range, which confers security and safety to the patients. Discussion Despite no apparent difference between bovine and porcine intestinal heparins in the haemodialysis practice, these two types of heparins should be used as distinct drugs due to their differences in structure and biological effects. Conclusions The reduced anticoagulant activity achieved in the plasma of patients under dialysis using bovine instead of porcine heparin did not affect significantly the patients or the dialyzer. PMID:23763719

Development and utilization of extracorporeal regional complexing hemodialysis as a means of mobilizing and enhancing the excretion of methylmercury in the dog. [N-acetylcysteine; N-acetylpenicillamine; 2,3-dimercaptosuccinic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostyniak, P.J.

1975-01-01

The present investigation was directed at developing and testing a new procedure for increasing methylmercury excretion in the dog. The procedure utilizes hemodialysis in conjunction with the extracorporeal reversal of protein binding of methylmercury in blood by the presence of low molecular weight sulfhydryl containing complexing agents (cysteine, N-acetylcysteine, penicillamine, N-acetylpenicillamine, 2,3-dimercaptosuccinic acid) having a high chemical affinity for methylmercury. Using such a procedure, the complexed methylmercury and the free complexing agent were found to be readily removed from blood by the dialyzer. Unlike chelation therapy, this procedure does not rely on the attainment of high systemic concentrations of complexingmore » agent in order to attain enhanced excretion by normal routes. It rather introduces into the circulatory system a shunt designed specifically for methylmercury extraction from blood. In vitro testing of this procedure revealed that methylmercury removal from blood was dependent upon the concentration of complexing agent in blood and the dialyzer blood flow rate. In vivo testing of the procedure in the dog utilized a standard hemodialyzer with infusion of complexing agent into the arterial dialyzer blood line. The rate of methylmercury removal from the dog during the treatment procedures were as high as 400 times the excretion rate of mercury in untreated dogs.« less

SNF472, a novel inhibitor of vascular calcification, could be administered during hemodialysis to attain potentially therapeutic phytate levels.

PubMed

Perelló, Joan; Gómez, M; Ferrer, M D; Rodríguez, N Y; Salcedo, C; Buades, J M; Pérez, M M; Torregrosa, J V; Martín, E; Maduell, F

2018-04-01

Cardiovascular calcification (CVC) is a major concern in hemodialysis (HD) and the loss of endogenous modulators of calcification seems involved in the process. Phytate is an endogenous crystallization inhibitor and its low molecular mass and high water solubility make it potentially dialyzable. SNF472 (the hexasodium salt of phytate) is being developed for the treatment of calciphylaxis and CVC in HD patients. We aimed to verify if phytate is lost during dialysis, and evaluate SNF472's behaviour during dialysis. Dialyzability was assessed in vitro using online-hemodiafiltration and high-flux HD systems in blood and saline. SNF472 was infused for 20 min and quantified at different time points. Phytate completely dialyzed in 1 h at low concentrations (10 mg/l) but not when added at 30 or 66.67 mg/l SNF472. In bypass conditions, calcium was slightly chelated during SNF472 infusion but when the system was switched to dialysis mode the calcium in the bath compensated this chelation. Phytate dialyses with a low clearance. The administration of SNF472 as an exogenous source of phytate allows to attain supra-physiological levels required for its potential therapeutic properties. As SNF472 is infused during the whole dialysis session, the low clearance would not affect the drug's systemic exposure.

Reconstitution of the Light Harvesting Chlorophyll a/b Pigment-Protein Complex into Developing Chloroplast Membranes Using a Dialyzable Detergent 1

PubMed Central

Darr, Sylvia C.; Arntzen, Charles J.

1986-01-01

Conditions were developed to isolate the light-harvesting chlorophyll-protein complex serving photosystem II (LHC-II) using a dialyzable detergent, octylpolyoxyethylene. This LHC-II was successfully reconstituted into partially developed chloroplast thylakoids of Hordeum vulgare var Morex (barley) seedlings which were deficient in LHC-II. Functional association of LHC-II with the photosystem II (PSII) core complex was measured by two independent functional assays of PSII sensitization by LHC-II. A 3-fold excess of reconstituted LHC-II was required to equal the activity of LHC developing in vivo. We suggest that a linker component may be absent in the partially developed membranes which is required for specific association of the PSII core complex and LHC-II. Images Fig. 1 PMID:16664744

NxStage dialysis system-associated thrombocytopenia: a report of two cases.

PubMed

Sekkarie, Mohamed; Waldron, Michelle; Reynolds, Texas

2016-01-01

Thrombocytopenia in hemodialysis patients has recently been reported to be commonly caused by electron-beam sterilization of dialysis filters. We report the occurrence of thrombocytopenia in the first two patients of a newly established home hemodialysis program. The 2 patients switched from conventional hemodialysis using polysulfone electron-beam sterilized dialyzers to a NxStage system, which uses gamma sterilized polyehersulfone dialyzers incorporated into a drop-in cartridge. The thrombocytopenia resolved after return to conventional dialysis in both patients and recurred upon rechallenge in the patient who opted to retry NxStage. This is the first report of thrombocytopenia with the NxStage system according to the authors’ knowledge. Dialysis-associated thrombocytopenia pathophysiology and clinical significance are not well understood and warrant additional investigations.

A secreted protein is an endogenous chemorepellant in Dictyostelium discoideum

PubMed Central

Phillips, Jonathan E.; Gomer, Richard H.

2012-01-01

Chemorepellants may play multiple roles in physiological and pathological processes. However, few endogenous chemorepellants have been identified, and how they function is unclear. We found that the autocrine signal AprA, which is produced by growing Dictyostelium discoideum cells and inhibits their proliferation, also functions as a chemorepellant. Wild-type cells at the edge of a colony show directed movement outward from the colony, whereas cells lacking AprA do not. Cells show directed movement away from a source of recombinant AprA and dialyzed conditioned media from wild-type cells, but not dialyzed conditioned media from aprA− cells. The secreted protein CfaD, the G protein Gα8, and the kinase QkgA are necessary for the chemorepellant activity of AprA as well as its proliferation-inhibiting activity, whereas the putative transcription factor BzpN is dispensable for the chemorepellant activity of AprA but necessary for inhibition of proliferation. Phospholipase C and PI3 kinases 1 and 2, which are necessary for the activity of at least one other chemorepellant in Dictyostelium, are not necessary for recombinant AprA chemorepellant activity. Starved cells are not repelled by recombinant AprA, suggesting that aggregation-phase cells are not sensitive to the chemorepellant effect. Cell tracking indicates that AprA affects the directional bias of cell movement, but not cell velocity or the persistence of cell movement. Together, our data indicate that the endogenous signal AprA acts as an autocrine chemorepellant for Dictyostelium cells. PMID:22711818

Effectiveness of Haemodiafiltration with Heat Sterilized High-Flux Polyphenylene HF Dialyzer in Reducing Free Light Chains in Patients with Myeloma Cast Nephropathy

PubMed Central

2015-01-01

Introduction In cases of myeloma cast nephropathy in need of haemodialysis (HD), reduction of free light chains using HD with High-Cut-Off filters (HCO-HD), in combination with chemotherapy, may be associated with better renal recovery. The aim of the present study is to evaluate the effectiveness of haemodiafiltration (HDF) in reducing free light chain levels using a less expensive heat sterilized high-flux polyphenylene HF dialyzer (HF-HDF). Methods In a single-centre prospective cohort study, 327 dialysis sessions were performed using a 2.2 m2 heat sterilized high-flux polyphenylene HF dialyzer (Phylther HF22SD), a small (1.1m2) or large (2.1 m2) high-cut-off (HCO) dialyzer (HCOS and HCOL) in a cohort of 16 patients presenting with dialysis-dependent acute cast nephropathy and elevated free light chains (10 kappa, 6 lambda). The outcomes of the study were the mean reduction ratio (RR) of kappa and lambda, the proportion of treatments with an RR of at least 0.65, albumin loss and the description of patient outcomes. Statistical analysis was performed using linear and logistic regression through generalized estimating equation analysis so as to take into account repeated observation within subjects and adjust for session duration. Results There were no significant differences in the estimated marginal mean of kappa RR, which were respectively 0.67, 0.69 and 0.70 with HCOL-HD, HCOS-HDF and HF-HDF (P = 0.950). The estimated marginal mean of the proportions of treatments with a kappa RR ≥0.65 were 68%, 63% and 71% with HCOL-HD, HCOS-HDF and HF-HDF, respectively (P = 0.913). The estimated marginal mean of lambda RR were higher with HCOL-HDF (0.78), compared to HCOL-HD and HF-HDF (0.62, and 0.61 respectively). The estimated marginal mean proportion of treatments with a lambda RR ≥0.65 were higher with HCOL-HDF (81%), compared to 57% in HF-HDF (P = 0.042). The median albumin loss were 7, 21 and 63 g/session with HF-HDF, HCOL-HD and HCOL-HDF respectively (P = 0.044). Among survivors, 9 out of 10 episodes of acute kidney injuries became dialysis-independent following a median time of renal replacement therapy of 40 days (range 7–181). Conclusion Therefore, in patients with acute dialysis-dependent myeloma cast nephropathy, in addition to chemotherapy, HDF with a heat sterilized high-flux polyphenylene HF dialyzer could offer an alternative to HCO dialysis for extracorporeal kappa reduction with lower albumin loss. PMID:26466100

Your Dialysis Care Team

MedlinePlus

... A to Z Health Guide Your Dialysis Care Team Tweet Share Print Email Good health care is ... dialyzers (artificial kidneys) for reuse. Vascular Access Care Team If you are a hemodialysis patient, another group ...

A Single-Dose, Open-Label Study of the Pharmacokinetics, Safety, and Tolerability of Lisdexamfetamine Dimesylate in Individuals With Normal and Impaired Renal Function

PubMed Central

Ermer, James; Corcoran, Mary; Lasseter, Kenneth; Marbury, Thomas; Yan, Brian

2016-01-01

Background: Lisdexamfetamine (LDX) and d-amphetamine pharmacokinetics were assessed in individuals with normal and impaired renal function after a single LDX dose; LDX and d-amphetamine dialyzability was also examined. Methods: Adults (N = 40; 8/group) were enrolled in 1 of 5 renal function groups [normal function, mild impairment, moderate impairment, severe impairment/end-stage renal disease (ESRD) not requiring hemodialysis, and ESRD requiring hemodialysis] as estimated by glomerular filtration rate (GFR). Participants with normal and mild to severe renal impairment received 30 mg LDX; blood samples were collected predose and serially for 96 hours. Participants with ESRD requiring hemodialysis received 30 mg LDX predialysis and postdialysis separated by a washout period of 7–14 days. Predialysis blood samples were collected predose, serially for 72 hours, and from the dialyzer during hemodialysis; postdialysis blood samples were collected predose and serially for 48 hours. Pharmacokinetic end points included maximum plasma concentration (Cmax) and area under the plasma concentration versus time curve from time 0 to infinity (AUC0–∞) or to last assessment (AUClast). Results: Mean LDX Cmax, AUClast, and AUC0–∞ in participants with mild to severe renal impairment did not differ from those with normal renal function; participants with ESRD had higher mean Cmax and AUClast than those with normal renal function. d-amphetamine exposure (AUClast and AUC0–∞) increased and Cmax decreased as renal impairment increased. Almost no LDX and little d-amphetamine were recovered in the dialyzate. Conclusions: There seems to be prolonged d-amphetamine exposure after 30 mg LDX as renal impairment increases. In individuals with severe renal impairment (GFR: 15 ≤ 30 mL·min−1·1.73 m−2), the maximum LDX dose is 50 mg/d; in patients with ESRD (GFR: <15 mL·min−1·1.73 m−2), the maximum LDX dose is 30 mg/d. Neither LDX nor d-amphetamine is dialyzable. PMID:26926668

A STUDY OF THE COMPONENTS OF THE CORNIFIED EPITHELIUM OF HUMAN SKIN

PubMed Central

Matoltsy, A. Gedeon; Balsamo, Constance A.

1955-01-01

Pulverized cornified epithelium of human skin was divided into a "soluble fraction" and a "residue." About half of the "soluble fraction" proved to be soluble epidermal keratin (keratin A); the remainder, dialyzable substances of low molecular weight. The "residue" contained epidermal keratin and resistant cell membranes of cornified cells. Epidermal keratin was found to form an oriented and dense submicroscopic structure in the cornified cells. It showed high resistance toward strong acid and moderately strong alkali solutions as well as concentrated urea. In strong alkali, reducing substances, alkaline urea, and mixtures of reducing substance with alkali, epidermal keratin dissociated and yielded a non-dialyzable derivative of high molecular weight (keratin B) which resembled true proteins. The cell membranes of cornified cells showed higher resistance toward strong alkali and reducing substance than did epidermal keratin. PMID:13242598

Development of a dialyzer with enhanced internal filtration to increase the clearance of low molecular weight proteins.

PubMed

Fujimura, Takayasu; Uchi, Yukihiko; Fukuda, Makoto; Miyazaki, Miwa; Uezumi, Satoshi; Hiyoshi, Tatsuo

2004-01-01

Accumulated low molecular weight proteins in hemodialysis patients require a high-flux dialyzer. There have been several methods proposed for enhancing internal filtration, including narrowing the inside diameter of the hollow fibers, lengthening the fibers, and increasing the fiber density ratio. We tried to enhance the internal filtration by increasing the pressure drop in the dialysate compartment through increasing the fiber density ratio. If the fiber density ratio is too high, however, an irregular dialysate path may result, thus decreasing dialysis performance. Therefore, we took note of the shape of the inner housing and added a short taper structure, which improved the dialysate path dramatically. Consequently, we developed an internal filtration-enhanced dialyzer (APS-Prototype) to improve dialysis performance. The internal filtration rate in water (measured by Doppler ultrasound) was 13.2 l/session for the APS-Prototype and 5.3 l/session for the APS-15E. The amount of alpha1-microglobulin (alpha1-MG) in bovine plasma was 0.34 g for the APS-Prototype and 0.11 g for the APS-15E. In addition, the amount of alpha1-MG in vivo was 29.0% +/- 5.8% for the APS-Prototype, significantly higher than that for the APS-15E (13.6% +/- 1.9%). The desirable loss of albumin is 2-4 g in hemodiafiltration, and it was 3.92 +/- 1.03 g for the APS-Prototype. The prototype showed excellent solute removal performance with no clinical or engineering problems.

Pulmonary hypertension in hemodialysis patients without arteriovenous fistula: the effect of dialyzer composition.

PubMed

Kiykim, Ahmet Alper; Horoz, Mehmet; Ozcan, Turkay; Yildiz, Ibrahim; Sari, Sibel; Genctoy, Gultekin

2010-01-01

Pulmonary hypertension (PHT) increases mortality rate in hemodialysis (HD) patients. Numerous clinical, hemodynamic, and metabolic abnormalities have been suggested to be associated with the development of PHT in HD patients. We aimed to investigate the acute effects of two different dialyzer membranes on pulmonary arterial pressure (PAP) throughout a HD session in maintenance HD patients. Seventy-four HD patients dialyzed through permanent tunneled jugular central venous catheter were enrolled. A first-use cellulose acetate and high-flux polysulfone dialysis membrane were tested using a crossover design. For each membrane, pre- and post-dialysis pulmonary artery pressures were measured echocardiographically. Elevated pulmonary artery pressure was observed in 68.8% of patients (n = 51), whereas mild PHT was observed in 28.3% of patients (n = 21) and moderate PHT in 40.5% (n = 30). Decrease in pulmonary artery pressure following HD procedure performed using high-flux polysulfone membrane was significantly higher than the decrease observed following HD procedure performed using cellulose acetate membrane (p < 0.05). Significant decrease in pulmonary artery pressures was observed only after HD procedures performed using high-flux polysulfone membrane (p < 0.05). Ultrafiltered volume was only significantly correlated with the decrease in pulmonary artery pressure observed after HD procedure performed through high-flux polysulfone membrane (β = 0.411, p < 0.05). PHT seems to be prevalent among HD patients even in the absence of AV fistula and abnormal cardiac functions. Membrane composition seems to be important, which may overwhelm the improving effects of ultrafiltration.

Cerebral metabolic alterations and cognitive dysfunction in children with chronic kidney disease using Magnetic Resonance Spectroscopy and Wechsler intelligence scale.

PubMed

Youssef, Doaa Mohammed; Mohamed, Ahmed Hosny; Kamel Attia, Wafaa Mahmoud; Mohammad, Faten Fawzy; El Fatah, Nelly Rafaat Abd; Elshal, Amal Saeed

2017-06-16

Many studies described Impaired intelligence, attention, memory and executive function in patients with chronic kidney disease (CKD) dialyzed and non-dialyzed, but there is still lacking the early and sensitive method of detection of these deficits. The purpose of this study is to investigate relation between the brain metabolic alteration [measured by magnetic resonance spectroscopy (MRS)] and cognitive dysfunction in CKD children (detected by psychometric analysis). One hundred and forty patients with CKD were included [ 40 patients with stage 5 CKD on dialysis, 30 patients with stage 4 to 5 CKD without dialysis, and 70 patients with stage 1 to 3 CKD]. All patients with previous neurological disorders were excluded. Conventional MRI, MRS and psychometric assessment by using Wechsler intelligence scale for children third edition was done in all subjects. We found a significant negative correlation between MRS abnormalities and Wechsler IQ Test scores. But there was a significantly positive correlation between the CKD stages and MRS abnormalities in patients with CKD and negative significant correlation between CKD stages and Wechsler IQ test scores in patients with CKD. There were correlations between "the electrolyte disturbance, blood hemoglobin and hypertension" and "the CKD staging, cognitive functions IQ scores and MRS parameter changes". We concluded that both MRS and psychometric tests are sensitive methods for detection of cognitive function affection in CKD children, particularly in dialyzed group and these findings appears before the clinical diagnosis. This article is protected by copyright. All rights reserved.

Hemodialysis and nutritional status in children: malnutrition and cachexia.

PubMed

Fischbach, Michel; Dheu, Céline; Seuge, Laure; Orfanos, Nadia

2009-01-01

Malnutrition is a common state in chronic hemodialyzed children. More than malnutrition, which infers that dietary supplementation would be curative, cachexia, which implies loss of protein stores, are combined factors of impaired linear growth and reduced muscle mass in uremic patients. Adequate diet to prevent malnutrition is of major importance. But to avoid cachexia in children on chronic hemodialysis, the management of acidosis, inflammation, abnormal metabolic rate, and endocrine disturbances should not, be forgotten. Daily hemodialysis regimen using convective flow therapy and ultrapure dialysate, i.e., on line hemodiafiltration together with growth hormone therapy, appears as a hopeful strategy for the chronic dialyzed child to achieve catch-up growth, a parameter of optimal nutrition.

Metabolic bone disease in chronic renal failure. II. Renal transplant patients.

PubMed Central

Huffer, W. E.; Kuzela, D.; Popovtzer, M. M.; Starzl, T. E.

1975-01-01

Trabecular vertebral bone of renal transplant patients was quantitatively compared with bone from normal individuals and dialyzed and nondialyzed patienets with chronic renal failure reported in detail in an earlier study. Long- and short-term transplant patients have increased bone resorption and mineralization defects similar to renal osteodystrophy in dialyzed and nondialyzed patients. However, in transplant patients the magnitude of resorption is greater, and bone volume tends to decrease rather than increase. Resorptive activity in transplant patients is maximal during the first year after transplantation. Bone volume decreases continuously for at least 96 months after transplantation. Only decreased bone volume correlated with success or failure of the renal transplant. Morphologic findings in this study correlate with other clinical and morphologic data to suggest that reduction in bone volume in transplant patients results from a combination of persistent hyperparathyroidism and suppression of bone formation by steroid therapy. Images Fig 1 PMID:1091152

[Calculating the optimum size of a hemodialysis unit based on infrastructure potential].

PubMed

Avila-Palomares, Paula; López-Cervantes, Malaquías; Durán-Arenas, Luis

2010-01-01

To estimate the optimum size for hemodialysis units to maximize production given capital constraints. A national study in Mexico was conducted in 2009. Three possible methods for estimating a units optimum size were analyzed: hemodialysis services production under monopolistic market, under a perfect competitive market and production maximization given capital constraints. The third method was considered best based on the assumptions made in this paper; an optimal size unit should have 16 dialyzers (15 active and one back up dialyzer) and a purifier system able to supply all. It also requires one nephrologist, five nurses per shift, considering four shifts per day. Empirical evidence shows serious inefficiencies in the operation of units throughout the country. Most units fail to maximize production due to not fully utilizing equipment and personnel, particularly their water purifier potential which happens to be the most expensive asset for these units.

Hemodiafiltration improves free light chain removal and normalizes κ/λ ratio in hemodialysis patients.

PubMed

Bourguignon, Chloé; Chenine, Leïla; Bargnoux, Anne Sophie; Leray-Moragues, Hélène; Canaud, Bernard; Cristol, Jean-Paul; Morena, Marion

2016-04-01

Serum free light chain (FLC) levels are correlated with chronic kidney disease (CKD) stages and are highest in patients on hemodialysis (HD). Aim of this study was to assess the FLC removal efficiency of Elisio™-210H dialyzer using either high-flux HD or on line high efficiency hemodiafiltration (HDF) modalities in CKD-5D patients. In this prospective and comparative study, 20 CKD-5D patients free from multiple myeloma were randomized in two groups: HD versus on line HDF. All patients were dialyzed with Elisio™-210H dialyzer. Serum samples were collected before and after the midweek dialysis session, before randomization and at the end of the study to measure κ and λ FLC concentrations. Reduction ratios were corrected for net ultrafiltration. For both HD and HDF mode, κ and λ FLC concentrations were significantly lower after dialysis than before but median reductions in κ and λ FLC levels were significantly higher in HDF versus HD groups (κ 73.5 vs. 65.5 %, p = 0.04 and λ 51.0 vs. 36.6 %, p = 0.07). After dialysis, all κ/λ ratio values were between 0.26 and 1.65 which is the reference range described in subjects with normal kidney function, for both HD and HDF groups (median κ/λ ratios were 0.80 [0.47-1.22] and 0.67 [0.50-0.79] respectively). This study shows the superiority of on line HDF compared with HD to remove both κ and λ FLC. Moreover, all post-dialysis κ/λ ratios reached normal reference range.

Vitamin E-coated polysulfone membrane improved red blood cell antioxidant status in hemodialysis patients.

PubMed

Bargnoux, Anne-Sophie; Cristol, Jean-Paul; Jaussent, Isabelle; Chalabi, Lotfi; Bories, Pierre; Dion, Jean-Jacques; Henri, Patrick; Delage, Martine; Dupuy, Anne-Marie; Badiou, Stéphanie; Canaud, Bernard; Morena, Marion

2013-01-01

Oxidative stress has emerged as a strong pathogenic cofactor implicated in the development of long-term complications in hemodialysis (HD) patients, such as anemia, and as a major component of the malnutrition inflammation complex syndrome. This prospective multicenter study aimed at evaluating the short-term effects of the new vitamin E (vitE)-coated polysulfone (PS) membrane (VitabranE) on biocompatibility performances and anemia in HD patients. After a 3-month washout period with a high-flux synthetic dialyzer, 43 HD patients were switched to a vitE-PS dialyzer. Sampling was performed at baseline (corresponding to the end of the washout period) and after 1, 2 and 3 months of treatment. Oxidative stress status, as well as inflammatory parameters, was investigated at the end of each study period. Hemoglobin levels and administered doses of recombinant human erythropoietin or epoetin (EPO) were available in each center. The use of vitE-coated membranes for 3 months was not associated with any change in inflammatory parameters. By contrast, vitE-PS dialyzer resulted in a progressive increase in red blood cell (RBC) vitE concentration and in RBC superoxide dismutase activity. A concomitant progressive significant decrease in advanced oxidation protein product concentration at 2 months was observed, suggesting a preventive effect on oxidative stress. Finally, a significant decrease of the erythropoietin resistance index was obtained after 3 months of treatment. Use of the vitE-PS membrane during a short period improves erythrocyte antioxidant defense mechanisms and seems to lead to a reduction in EPO requirements in HD patients.

Biocompatibility and permeability of dialyzer membranes do not affect anemia, erythropoietin dosage or mortality in japanese patients on chronic non-reuse hemodialysis: a prospective cohort study from the J-DOPPS II study.

PubMed

Yokoyama, Hitoshi; Kawaguchi, Takehiko; Wada, Takashi; Takahashi, Yoshinori; Higashi, Takahiro; Yamazaki, Shin; Fukuhara, Shunichi; Akiba, Takashi; Akizawa, Tadao; Asano, Yasushi; Kurokawa, Kiyoshi; Saito, Akira

2008-01-01

Considerable controversy exists over the impact of the biocompatibility and flux characteristics of dialyzer membranes on anemia in chronic hemodialysis patients. A subset of 1,207 subjects from the Japanese arm of DOPPS phase II was analyzed. Patient characteristics included mean age 59 years, male sex 60%, BMI 20.6, time on dialysis therapy 7.8 years, and diabetes rate 27%. Dialysis parameters were Kt/V 1.33, and normalized protein catabolic rate 1.05 g/kg/day. Initial hemoglobin level was 10.1 g/dl. 79% were treated by intravenous erythropoietin with mean weekly doses of 4,500 IU. Hemoglobin levels and erythropoietin doses during 2-year study period were not affected by dialysis membrane biocompatibility (unmodified cellulose or biocompatible) or flux (standard or high performance). The 2-year survival rate was 90.9% and was influenced by older age, presence of cardiovascular diseases and amyloidosis, lower levels of BMI and serum albumin, but not by other variables, including dialysis membranes. Use of biocompatible membranes was associated with a lower all-cause mortality (8.3 vs. 13.0% for bioincompatible, p = 0.037), but this difference was not significant in multivariate analyses (hazard ratio 0.70, p = 0.17 by Cox multivariate analysis). The biocompatibility and permeability of dialyzer membranes had no effect on anemia, erythropoietin dosage or all-cause mortality in Japanese chronic hemodialysis patients treated by non-reuse dialysis. Copyright 2008 S. Karger AG, Basel.

Creatinine generation from kinetic modeling with or without postdialysis serum creatinine measurement: results from the HEMO study.

PubMed

Daugirdas, John T; Depner, Thomas A

2017-11-01

A convenient method to estimate the creatinine generation rate and measures of creatinine clearance in hemodialysis patients using formal kinetic modeling and standard pre- and postdialysis blood samples has not been described. We used data from 366 dialysis sessions characterized during follow-up month 4 of the HEMO study, during which cross-dialyzer clearances for both urea and creatinine were available. Blood samples taken at 1 h into dialysis and 30 min and 60 min after dialysis were used to determine how well a two-pool kinetic model could predict creatinine concentrations and other kinetic parameters, including the creatinine generation rate. An extrarenal creatinine clearance of 0.038 l/kg/24 h was included in the model. Diffusive cross-dialyzer clearances of urea [230 (SD 37 mL/min] correlated well (R2 = 0.78) with creatinine clearances [164 (SD 30) mL/min]. When the effective diffusion volume flow rate was set at 0.791 times the blood flow rate for the cross-dialyzer clearance measurements at 1 h into dialysis, the mean calculated volume of creatinine distribution averaged 29.6 (SD 7.2) L], compared with 31.6 (SD 7.0) L for urea (P < 0.01). The modeled creatinine generation rate [1183 (SD 463) mg/day] averaged 100.1 % (SD 29; median 99.3) of that predicted in nondialysis patients by an anthropometric equation. A simplified method for modeling the creatinine generation rate using the urea distribution volume and urea dialyzer clearance without use of the postdialysis serum creatinine measurement gave results for creatinine generation rate [1187 (SD 475) mg/day; that closely matched the value calculated using the formally modeled value, R2 = 0.971]. Our analysis confirms previous findings of similar distribution volumes for creatinine and urea. After taking extra-renal clearance into consideration, the creatinine generation rate in dialysis patients is similar to that in nondialysis patients. A simplified method based on urea clearance and urea distribution volume not requiring a postdialysis serum creatinine measurement can be used to yield creatinine generation rates that closely match those determined from standard modeling. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

A study on trypsin, Aspergillus flavus and Bacillus sp. protease inhibitory activity in Cassia tora (L.) syn Senna tora (L.) Roxb. seed extract.

PubMed

Tripathi, Vinayak R; Kumar, Shailendra; Garg, Satyendra K

2011-07-12

Proteases play an important role in virulence of many human, plant and insect pathogens. The proteinaceous protease inhibitors of plant origin have been reported widely from many plant species. The inhibitors may potentially be used for multiple therapeutic applications in viral, bacterial, fungal diseases and physiological disorders. In traditional Indian medicine system, Cassia tora (Senna tora) is reportedly effective in treatment of skin and gastrointestinal disorders. The present study explores the protease inhibitory activity of the above plant seeds against trypsin, Aspergillus flavus and Bacillus sp. proteases. The crushed seeds of Cassia tora were washed thoroughly with acetone and hexane for depigmentation and defatting. The proteins were fractionated by ammonium sulphate (0-30, 30-60, 60-90%) followed by dialysis and size exclusion chromatography (SEC). The inhibitory potential of crude seed extract and most active dialyzed fraction against trypsin and proteases was established by spot test using unprocessed x-ray film and casein digestion methods, respectively. Electrophoretic analysis of most active fraction (30-60%) and SEC elutes were carried employing Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Gelatin SDS-PAGE. Inhibition of fungal spore germination was studied in the presence of dialyzed active inhibitor fraction. Standard deviation (SD) and ANOVA were employed as statistical tools. The crude seeds' extract displayed strong antitryptic, bacterial and fungal protease inhibitory activity on x-ray film. The seed protein fraction 30-60% was found most active for trypsin inhibition in caseinolytic assay (P < 0.001). The inhibition of caseinolytic activity of the proteases increased with increasing ratio of seed extract. The residual activity of trypsin, Aspergillus flavus and Bacillus sp. proteases remained only 4, 7 and 3.1%, respectively when proteases were incubated with 3 mg ml-1 seed protein extract for 60 min. The inhibitory activity was evident in gelatin SDS-PAGE where a major band (~17-19 kD) of protease inhibitor (PI) was detected in dialyzed and SEC elute. The conidial germination of Aspergillus flavus was moderately inhibited (30%) by the dialyzed seed extract. Cassia tora seed extract has strong protease inhibitory activity against trypsin, Aspergillus flavus and Bacillus sp. proteases. The inhibitor in Cassia tora may attenuate microbial proteases and also might be used as phytoprotecting agent. © 2011 Tripathi et al; licensee BioMed Central Ltd.

Two-dimensional HPLC coupled to ICP-MS and electrospray ionisation (ESI)-MS/MS for investigating the bioavailability in vitro of arsenic species from edible seaweed.

PubMed

Garcia-Sartal, Cristina; Taebunpakul, Sutthinun; Stokes, Emma; Barciela-Alonso, María del Carmen; Bermejo-Barrera, Pilar; Goenaga-Infante, Heidi

2012-04-01

Edible seaweed consumption is a route of exposure to arsenic. However, little attention has been paid to estimate the bioaccessibility and/or bioavailability of arsenosugars in edible seaweed and their possible degradation products during gastrointestinal digestion. This work presents first use of combined inductively coupled plasma mass spectroscopy (ICP-MS) with electrospray ionization tandem mass spectrometry (ESI-MS/MS) with two-dimensional HPLC (size exclusion followed by anion exchange) to compare the qualitative and quantitative arsenosugars speciation of different edible seaweed with that of their bioavailable fraction as obtained using an in vitro gastrointestinal digestion procedure. Optimal extraction conditions for As species from four seaweed namely kombu, wakame, nori and sea lettuce were selected as a compromise between As extraction efficiency and preservation of compound identity. For most investigated samples, the use of ammonium acetate buffer as extractant and 1 h sonication in a water bath followed by HPLC-ICP-MS resulted in 40-61% of the total As to be found in the buffered aqueous extract, of which 86-110% was present as arsenosugars (glycerol sugar, phosphate sugar and sulfonate sugar for wakame and kombu and glycerol sugar and phosphate sugar for nori). The exception was sea lettuce, for which the arsenosugar fraction (glycerol sugar, phosphate sugar) only comprised 44% of the total extracted As. Interestingly, the ratio of arsenobetaine and dimethylarsinic acid to arsenosugars in sea lettuce extracts seemed higher than that for the rest of investigated samples. After in vitro gastrointestinal digestion, approximately 11-16% of the total As in the solid sample was found in the dialyzates with arsenosugars comprising 93-120% and 41% of the dialyzable As fraction for kombu, wakame, nori and sea lettuce, respectively. Moreover, the relative As species distribution in seaweed-buffered extracts and dialyzates was found to be very similar. Collection of specific fractions from the size-exclusion column to be analysed using anion-exchange HPLC-ESI-MS/MS enabled improved chromatographic selectivity, particularly for the less retained arsenosugar (glycerol sugar), facilitating confirmation of the presence of arsenosugars in seaweed extracts and dialyzates. Using this approach, the presence of arsenobetaine in sea lettuce samples was also confirmed.

Confirmation of Nosocomial Transmission of Hepatitis C Virus by Phylogenetic Analysis of the NS5-B Region

PubMed Central

Norder, Heléne; Bergström, Åsa; Uhnoo, Ingrid; Aldén, Jöran; Weiss, Lars; Czajkowski, Jan; Magnius, Lars

1998-01-01

Four hepatitis C virus transmission chains at three dialysis units were disclosed by limited sequencing; three of these were disclosed by analysis of the NS5-B region of the genome. Dialysis on the same shift as that during which infected patients were dialyzed was the common factor for seven patients in two chains. Two nurses exposed to needle sticks and their sources of infection constituted two other chains. The strains of three chains belonged to subtype 1a and formed clusters with an intrachain variability of 0 to 6 nucleotides compared to 8 to 37 nucleotides for unrelated strains within this subtype. The clusters were supported by bootstrap values ranging from 89 to 100%. PMID:9738071

In silico ordinary differential equation/partial differential equation hemodialysis model estimates methadone removal during dialysis.

PubMed

Linares, Oscar A; Schiesser, William E; Fudin, Jeffrey; Pham, Thien C; Bettinger, Jeffrey J; Mathew, Roy O; Daly, Annemarie L

2015-01-01

There is a need to have a model to study methadone's losses during hemodialysis to provide informed methadone dose recommendations for the practitioner. To build a one-dimensional (1-D), hollow-fiber geometry, ordinary differential equation (ODE) and partial differential equation (PDE) countercurrent hemodialyzer model (ODE/PDE model). We conducted a cross-sectional study in silico that evaluated eleven hemodialysis patients. Patients received a ceiling dose of methadone hydrochloride 30 mg/day. Outcome measures included: the total amount of methadone removed during dialysis; methadone's overall intradialytic mass transfer rate coefficient, km ; and, methadone's removal rate, j ME. Each metric was measured at dialysate flow rates of 250 mL/min and 800 mL/min. The ODE/PDE model revealed a significant increase in the change of methadone's mass transfer with increased dialysate flow rate, %Δkm =18.56, P=0.02, N=11. The total amount of methadone mass transferred across the dialyzer membrane with high dialysate flow rate significantly increased (0.042±0.016 versus 0.052±0.019 mg/kg, P=0.02, N=11). This was accompanied by a small significant increase in methadone's mass transfer rate (0.113±0.002 versus 0.014±0.002 mg/kg/h, P=0.02, N=11). The ODE/PDE model accurately predicted methadone's removal during dialysis. The absolute value of the prediction errors for methadone's extraction and throughput were less than 2%. ODE/PDE modeling of methadone's hemodialysis is a new approach to study methadone's removal, in particular, and opioid removal, in general, in patients with end-stage renal disease on hemodialysis. ODE/PDE modeling accurately quantified the fundamental phenomena of methadone's mass transfer during hemodialysis. This methodology may lead to development of optimally designed intradialytic opioid treatment protocols, and allow dynamic monitoring of outflow plasma opioid concentrations for model predictive control during dialysis in humans.

Influence of dialysis membrane composition on plasma bisphenol A levels during online hemodiafiltration.

PubMed

Mas, Sebastian; Bosch-Panadero, Enrique; Abaigar, Pedro; Camarero, Vanesa; Mahillo, Ignacio; Civantos, Esther; Sanchez-Ospina, Didier; Ruiz-Priego, Alberto; Egido, Jesus; Ortiz, Alberto; González-Parra, Emilio

2018-01-01

Bisphenol A (BPA) is an ubiquitous environmental toxin that is also found in dialyzers. Online hemodiafiltration (OL-HDF) more efficiently clears high molecular weight molecules, and this may improve BPA clearance. However, the BPA contents of dialysis membranes may be a source of BPA loading during OL-HDF. A prospective study assessed plasma BPA levels in OL-HDF patients using BPA-free (polynephron) or BPA-containing (polysulfone) dialyzers in a crossover design with two arms, after a run-in OL-HDF period of at least 6 months with the same membrane: 31 patients on polynephron at baseline were switched to polysulfone membranes for 3 months (polynephron-to-polysulfone) and 29 patients on polysulfone were switched to polynephron for 3 months (polysulfone-to-polynephron). After a run-in OL-HDF period of at least 6 months with the same membrane, baseline pre-dialysis BPA was lower in patients on polynephron (8.79±7.97 ng/ml) than in those on polysulfone (23.42±20.38 ng/mL, p<0.01), but still higher than in healthy controls (<2 ng/mL). After 3 months of polynephron-to-polysulfone switch, BPA was unchanged (8.98±7.88 to 11.14±15.98 ng/mL, ns) while it decreased on the polysulfone-to-polynephron group (23.42±20.38 to 11.41±12.38 ng/mL, p<0.01). OL-HDF for 3 months with BPA-free dialyzer membranes was associated to a significant decrease in predialysis BPA levels when compared to baseline BPA levels while on a BPA-containing membrane.

Influence of dialysis membrane composition on plasma bisphenol A levels during online hemodiafiltration

PubMed Central

Abaigar, Pedro; Camarero, Vanesa; Mahillo, Ignacio; Civantos, Esther; Sanchez-Ospina, Didier; Ruiz-Priego, Alberto; Egido, Jesus; Ortiz, Alberto; González-Parra, Emilio

2018-01-01

Introduction Bisphenol A (BPA) is an ubiquitous environmental toxin that is also found in dialyzers. Online hemodiafiltration (OL-HDF) more efficiently clears high molecular weight molecules, and this may improve BPA clearance. However, the BPA contents of dialysis membranes may be a source of BPA loading during OL-HDF. Methods A prospective study assessed plasma BPA levels in OL-HDF patients using BPA-free (polynephron) or BPA-containing (polysulfone) dialyzers in a crossover design with two arms, after a run-in OL-HDF period of at least 6 months with the same membrane: 31 patients on polynephron at baseline were switched to polysulfone membranes for 3 months (polynephron-to-polysulfone) and 29 patients on polysulfone were switched to polynephron for 3 months (polysulfone-to-polynephron). Results After a run-in OL-HDF period of at least 6 months with the same membrane, baseline pre-dialysis BPA was lower in patients on polynephron (8.79±7.97 ng/ml) than in those on polysulfone (23.42±20.38 ng/mL, p<0.01), but still higher than in healthy controls (<2 ng/mL). After 3 months of polynephron-to-polysulfone switch, BPA was unchanged (8.98±7.88 to 11.14±15.98 ng/mL, ns) while it decreased on the polysulfone-to-polynephron group (23.42±20.38 to 11.41±12.38 ng/mL, p<0.01). Conclusion OL-HDF for 3 months with BPA-free dialyzer membranes was associated to a significant decrease in predialysis BPA levels when compared to baseline BPA levels while on a BPA-containing membrane. PMID:29529055

Effect of Membrane Permeability on Inflammation and Arterial Stiffness: A Randomized Trial

PubMed Central

Cheng, Yuk Lun; Leung, Chi Bon; Szeto, Cheuk Chun; Chow, Kai Ming; Kwan, Bonnie Ching-Ha; Ng, Esther Siu-Chun; Fok, Queenie Wing-Yi; Poon, Yuet Ling; Yu, Alex Wai-Yin

2010-01-01

Background and objectives: Both larger molecule removal and dialyzer biocompatibility have been implicated in the high-flux hemodialysis (HD)-associated favorable outcome. In an attempt to delineate the effect of membrane permeability, we performed a randomized, crossover study to compare the inflammatory biomarkers, lipid profile, and aortic pulse wave velocity (PWV) of two dialyzers that are composed of identical membranes but with different flux characteristics. Design, setting, participants, & measurements: Stable patients who had anuria and were on low-flux polysulfone membrane were randomly allocated either to HD with high-flux polyamide membrane (group A; 22 patients) or to HD with low-flux polyamide membrane (group B; 24 patients) for 24 weeks, then they were started on 24 weeks of the alternative HD treatment. Apart from the dialyzer, the dialysis prescription remained unchanged. Results: Nineteen patients from group A and 23 patients from group B completed the study. Predialysis β2-microglobulin levels decreased significantly when using the high-flux polyamide membrane. No difference between membranes was observed for serum albumin, high-sensitivity C-reactive protein, fibrinogen, IL-6, triglycerides, HDL cholesterol, LDL cholesterol, and lipoprotein(a) during the study. A significant increase in aortic PWV, a marker of aortic stiffness, was noted after patients switched from high-flux to low-flux polyamide membranes. Similarly, the rate of change in aortic PWV was significantly decreased with the use of the high-flux polyamide membrane. Conclusions: Our findings suggest that dialysis with polyamide membranes with different flux characteristics did not modify the inflammatory indices and lipid profile in stable HD patients; however, a seemingly beneficial effect on aortic stiffness was noted for patients who were maintained on high-flux polyamide membrane. PMID:20203165

Vitamin E-loaded dialyzer resets PBMC-operated cytokine network in dialysis patients.

PubMed

Libetta, Carmelo; Zucchi, Manuela; Gori, Elena; Sepe, Vincenzo; Galli, Francesco; Meloni, Federica; Milanesi, Fabio; Dal Canton, Antonio

2004-04-01

In hemodialysis patients the activity of stimulated Th1 lymphocytes is depressed, while Th2 cells are constitutively primed. Such phenomena may depend on monocyte activation and altered release of interleukin (IL)-12 and IL-18, which regulate Th cell differentiation. Reactive oxygen species (ROS) activate monocytes; therefore, a hemodialyzer with antioxidant activity would contrast ROS, prevent monocyte activation, reset IL-12 and IL-18 release, and restore Th1/Th2 balance. Ten patients on regular dialysis treatment (RDT) with cellulosic membrane (CM) were shifted to vitamin E-coated dialyzer (VE). During treatment with CM and after 3, 6, and 12 months of treatment with VE, peripheral blood mononuclear cells (PBMC) and purified CD4+ cells were isolated, and cultured, resting, mitogen-stimulated, and interferon gamma (IFNgamma), IL-4, IL-10, IL-12, and IL-18 release was measured. Vitamin E and A plasma levels and the effects of a single dialysis session on peripheral blood NO levels were assayed. The constitutive release of IL-4 and IL-10 by CD4+ cells was abated significantly by treatment with VE (nadir -77.8% and -55.3%, respectively, at 12 months). INFgamma release by mitogen-stimulated CD4+ recovered with VE (zenith +501% at 12 months). PBMC constitutive production of IL-12 and IL-18 was significantly reduced by VE (nadir at 12 months -64.7% and -51.3%, respectively). VE increased plasma levels of vitamins E and A. NO plasma levels fell after a single dialysis treatment with VE (-17%, P < 0.05) in contrast with CU (+27.1%, P < 0.05). The network of cytokines released by monocytes and Th cells is reset toward normality by treatment with vitamin E-coated dialyzer.

SureClick® (Darbepoetin alfa) can improve perceived satisfaction and competence for anemia treatment and increase self-administration in non-dialyzed patients with chronic kidney disease.

PubMed

Bonafont, Xavier; Romero, Ramón; Martínez, Isabel; del Pino, María D; Gil, José M; Aranda, Pedro; Roca, Ramón; Claverol, Joana; Cucala, Mercedes

2013-01-01

SureClick® is a prefilled pen for administration of darbepoetin alfa (DA) that is ready-to-use. We explored patient satisfaction with SureClick® compared with prefilled syringes (PFS). Multicenter, prospective, 6-months, observational study in non-dialyzed patients with chronic kidney disease (CKD) treated with DA in PFS who switched to SureClick® at baseline. Main outcomes were: change in Anemia Treatment Satisfaction Questionnaire (ATSQ-S), Perceived Competence for Anemia Scale (PCAS) and self-administration rate. We enrolled 132 patients with a mean(SD) age of 71.3 (14.6) years, 57.6% women. Mean(SD) ATSQ-S scores at baseline and final records were 25.5 (7.9) and 31.6 (4.9) (on a scale from 0 to 36 maximum satisfaction-, mean change: 6.2, 95%CI: 4.6-7.8, p<0.0001). The PCAS also increased significantly (4.3 (2.0) vs 5.6 (1.6), on a scale from 1 to 7 maximum competence, p<0.0001). At baseline 47.7% of patients self-administered DA with PFS, vs 74.2% with SureClick® (p<0.001). No significant changes in hemoglobin were observed (11.4 (0.5) vs 11.6 (1.3) g/dl, p=0.193). Two patients (1.5%) had adverse reactions to SureClick® (pain on application). Our results suggest that the change from PFS to SureClick® could increase patient satisfaction and perceived competence in anemia management in non-dialyzed CKD patients, and could increase the self-administration rate, thereby reducing use of health resources.

Hemodialysis dialyzers contribute to contamination of air microemboli that bypass the alarm system in the air trap.

PubMed

Stegmayr, C; Jonsson, P; Forsberg, U; Stegmayr, B

2008-04-01

Previous studies have shown that micrometer-sized air bubbles are introduced into the patient during hemodialysis. The aim of this study was to investigate, in vitro, the influence of dialysis filters on the generation of air bubbles. Three different kind of dialyzers were tested: one high-flux FX80 dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany), one low-flux F8HPS dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany) and a wet-stored APS-18u filter (Asahi Kasei Medical, Tokyo, Japan). The F8HPS was tested with pump flow ranging between 100 to 400 ml/min. The three filters were compared using a constant pump flow of 300 ml/min. Measurements were performed using an ultrasound Doppler instrument. In 90% of the series, bubbles were measured after the outlet line of the air trap without triggering an alarm. There were significantly more bubbles downstream than upstream of the filters F8HPS and FX80, while there was a significant reduction using the APS-18u. There was no reduction in the number of bubbles after passage through the air trap versus before the air trap (after the dialyzer). Increased priming volume reduced the extent of bubbles in the system. Data indicate that the air trap does not prevent air microemboli from entering the venous outlet part of the dialysis tubing (entry to the patient). More extended priming of the dialysis circuit may reduce the extent of microemboli that originate from dialysis filters. A wet filter may be favorable instead of dry-steam sterilized filters.

Clinical evaluation of plasma insulin and C-peptide levels with 3 different high-flux dialyzers in diabetic patients on hemodialysis.

PubMed

Abe, M; Okada, K; Maruyama, T; Inoshita, A; Ikeda, K; Uto, E; Kikuchi, F; Matsumoto, K

2008-10-01

Changes in plasma immunoreactive insulin (IRI) and connecting-peptide immunoreactivity (CPR) concentrations during hemodialysis (HD) were evaluated in diabetic HD patients with 3 different high-flux membranes. The removal properties of the membranes were compared. In this prospective controlled study, 15 stable diabetic patients on HD were randomly selected for 6 HD sessions with 3 different membranes: polysulfone (PS), cellulose triacetate (CTA), and polymethylmethacrylate (PMMA). Blood samples were obtained from the blood tubing at the arterial (A) site at the beginning and end of the sixth HD session. At 60 minutes after dialysis initiation, blood samples were obtained from both the A and venous (V) sites of the dialyzer to investigate the clearance and removal properties of the membranes. The plasma IRI and CPR levels decreased significantly at each time point with all 3 membranes. IRI clearance with the PS membrane was significantly higher than that with the CTA and PMMA membranes. No difference was observed in the IRI reduction rate between the 3 membranes. CPR clearance and reduction rate with the PMMA membrane were lower than with the PS and CTA membranes. No significant difference was observed in serum creatinine clearance and reduction rates between the 3 membranes; however, serum urea nitrogen clearance was significantly lower with the PMMA membrane compared with the PS and CTA membranes. A significantly high beta2-microglobulin clearance and reduction rate was achieved in the order PS > CTA > PMMA. Plasma IRI and CPR are cleared by HD; their clearance rates differ with the dialyzer membranes. Plasma IRI clearance with the PS membrane is higher than that with the CTA and PMMA membranes.

[Pharmacokinetics of salazosulfapyridine in a hemodialysis patient].

PubMed

Akiyama, Yuji; Fujimaki, Toshihisa; Sakurai, Yusei

2003-06-01

The patient was a 62-year-old female. Total gastrectomy was performed due to gastric ulcer in 1969. She was diagnosed as rheumatoid arthritis (RA) in 1985 and was developed to amyloidosis in 1991. She was started on hemodialysis (HD) for chronic renal failure in 1996. In 1998, her arthralgia was aggravated, and 100 mg/day of bucillamine was administered on the day of HD. Her arthralgia persisted, and switching to salazosulfapyridine (SASP) was considered. As there were no standards and no reports for the use of SASP in HD patients, we examined the pharmacokinetics of SASP and its metabolites, and compared our patient with the results of phase one study in normal subjects in Japan. In this case, the blood concentration of SASP was similar to that in healthy controls after single administration of 500 mg of SASP on the day of non-HD, while the concentration of sulfapyridine (SP) was higher than that in healthy donors. However, the blood concentrations of SASP, SP, and N4-acetyl-SP (AcSP) at 24 hours after administration were similar to those obtained in healthy men. SASP was not dialyzed, while about half of SP and AcSP, were dialyzed. In a five-day consecutive administration study also, the blood concentrations of these compounds on Day 5 were similar to those of phase one study, suggesting no accumulation. No adverse drug reaction was observed. As this case had the past history of total gastrectomy and amyloidosis, it is possible that this result is influenced by the factors. Therefore it is necessary to examine pharmacokinetics of SASP and its metabolites beforehand when administering this agent to other HD/RA patients.

Impact of hemodialysis dose and frequency on survival of patients on chronic hemodialysis in Lithuania during 1998-2005.

PubMed

Stankuvienė, Asta; Ziginskienė, Edita; Kuzminskis, Vytautas; Bumblytė, Inga Arūnė

2010-01-01

The question of the targets of dialysis dosing remains controversial since the beginning of the long-term dialysis treatment era. It is still uncertain if higher dialysis dose is better. The aim of our study was to investigate issues of dialysis dose in Lithuania during the period of 1998-2005 and to determine associations between hemodialysis dose and survival of patients on chronic hemodialysis. We analyzed data of all patients who started hemodialysis due to end-stage renal disease in Lithuania between January 1, 1998, and December 31, 2005. The information about hemodialysis frequency, duration, and adequacy (according to Kt/V) was obtained from medical documentation. The overall survival rate was estimated using the Kaplan-Meier method. Survival comparisons were made using the log-rank or Breslow tests. Univariate Cox proportional hazards analysis was used to select variables significantly associated with the risk of death; then these variables were included in multivariate Cox proportional hazards models. During the study period, from 2428 patients who started chronic hemodialysis, 58.5% of patients started hemodialysis three times a week. More than one-third (36.2%) of patients were dialyzed twice weekly, and 5.3% of patients started hemodialysis once weekly. Survival analysis revealed that patients dialyzed less than three times per week survived shorter than patients receiving a higher dialysis dose. Duration of HD session of ≤8 hours per week was an independent risk factor for mortality. A higher mean Kt/V was associated with better survival of patients on chronic hemodialysis. Dialysis frequency and weekly duration of HD sessions were dependent on HD accessibility in Lithuania during the period of 1998-2005. Better survival of patients on chronic hemodialysis was associated with a higher hemodialysis dose.

Protective potential of non-dialyzable material fraction of cranberry juice on the virulence of P. gingivalis and F. nucleatum mixed infection.

PubMed

Polak, David; Naddaf, Raja; Shapira, Lior; Weiss, Ervin I; Houri-Haddad, Yael

2013-07-01

Periodontitis is a polymicrobial infectious disease. A novel potential chemical treatment modality may lie in bacterial anti-adhesive materials, such as cranberry juice fractions. The aim of this study is to explore the effect of high molecular weight cranberry constituent (non-dialyzable material [NDM]) on the virulence of a mixed infection with Porphyromonas gingivalis and Fusobacterium nucleatum in mice. In vitro, the anti-adhesive property of NDM was validated on epithelial cell culture, and inhibition of coaggregation was tested using a coaggregation assay. The in vivo effect was tested on the outcome of experimental periodontitis induced by a P. gingivalis and F. nucleatum mixed infection, and also on the local host response using the subcutaneous chamber model of infection. Phagocytosis was also tested on RAW macrophages by the use of fluorescent-labeled bacteria. NDM was found to inhibit the adhesion of both species of bacteria onto epithelial cells and to inhibit coaggregation in a dose-dependent manner. NDM consumption by mice attenuated the severity of experimental periodontitis compared with a mixed infection without NDM treatment. In infected subcutaneous chambers, NDM alone reduced tumor necrosis factor-α (TNF-α) levels induced by the mixed infection. In vitro, NDM eliminated TNF-α expression by macrophages that were exposed to P. gingivalis and F. nucleatum, without impairing their viability. Furthermore, NDM increased the phagocytosis of P. gingivalis. The results indicate that the use of NDM may hold potential protective and/or preventive modalities in periodontal disease. Underlying mechanisms for this trait may perhaps be the anti-adhesive properties of NDM or its potential effect on inflammation.

Clinical outcomes of the high-performance membrane dialyzer.

PubMed

Koda, Yutaka

2011-01-01

HPM (high-performance membrane or high-flux membrane) has better biocompatibility and higher capacity to remove retention solutes of large molecular weight, which has been proven to be toxic especially to cardiovascular and skeletal organs. To date, several non-randomized observational studies have shown a reduction in morbidity and mortality in HPM-treated patients compared with low-flux conventional membrane. Meanwhile, two randomized controlled trials were unable to reveal the superiority of high-flux membrane in survival of all-cause mortality, but suggested a significant benefit by subgroup analyses or post-hoc analyses in patients with diabetes, hypoalbuminemia and long duration of prior dialysis. Thus, the results of the published studies are conflicting and it still cannot be explained whether the effect is based on the biocompatibility of the membrane or on the differences in the clearance of middle molecules, or on the microbiological purity of dialysate which improved simultaneously with the flux increment. As survival outcome might be determined by additional multiple confounding factors, dialysis-related or non-dialysis-related, investigations to control them are difficult to perform. Although the clinical results are non-conclusive and it is still unanswered how much large molecule removal is required to improve outcomes in routine clinical practice, there is a considerable amount of biological plausibility for high-flux dialysis or middle molecule removal. Further trials will be required to confirm what patient group benefits the most, the magnitude of advantages and how large the molecules are and how much molecule removal is acceptable using advanced high-performance dialyzers. Dispersing hazardous effects by a low-quality therapy should be taken more seriously than practicing a high-quality therapy of uncertain superiority. Copyright © 2011 S. Karger AG, Basel.

Cerebral oximetry values in dialyzed surgical patients: a comparison between hemodialysis and peritoneal dialysis.

PubMed

Papadopoulos, Georgios; Dounousi, Evangelia; Papathanasiou, Athanasios; Papathanakos, Georgios; Tzimas, Petros

2013-07-01

Cerebral tissue regional oxygen saturation (rSO2) through near-infrared spectroscopy (NIRS) is a method for non-invasive monitoring of cerebral tissue oxygenation. However, nowadays there is limited information on the level of cerebral tissue oxygenation in dialyzed end-stage renal disease (ESRD) surgical patients. The aim of this observational study was to evaluate the baseline cerebral rSO2 values, to compare values between hemodialysis (HD) and peritoneal dialysis (PD) patients and identify risk factors that could predict cerebral tissue oxygenation in these patients. Thirty-two ESRD patients (≥18 years old), scheduled to undergo elective minor or major surgery, were enrolled. Patients were allocated in two groups according to dialysis modality. Twenty-three patients were treated with HD and nine were treated with PD. Demographic and clinical characteristics, comorbidities and arterial hemoglobin oxygen saturation (SpO2) of the study population were recorded. Patients who were treated with HD had significant lower baseline rSO2 values compared with PD patients [median, 50% (28-63) vs. 63% (45-69), p = 0.002]. Hierarchical linear regression model analysis showed that preoperative Hb and SpO2 were positive predictive variables (B = 0.353, p = 0.01 and B = 0.375, p = 0.009, respectively) for rSO2. Moreover, dialysis modality was independent predictor for baseline rSO2. The modality of dialysis remained an independent predictor for rSO2 after controlling for the other significant variables (B = 0.291, p = 0.032) and PD was associated with higher baseline values of rSO2. In conclusion, ESRD surgical patients undergoing PD treatment appear to have significantly higher baseline cerebral tissue saturation values compared with HD.

Challenges of hemodialysis in Vietnam: experience from the first standardized district dialysis unit in Ho Chi Minh City.

PubMed

Duong, Cuong Minh; Olszyna, Dariusz Piotr; Nguyen, Phong Duy; McLaws, Mary-Louise

2015-08-01

Hemodialysis is an increasingly common treatment in Vietnam as the diagnosis of end stage renal disease continues to rise. To provide appropriate hemodialysis treatment for end-stage renal disease patients, we conducted a 1-year cross-sectional study to measure the prevalence of bloodborne infection and factors associated with non-compliant behaviors in hemodialysis patients. One hundred forty-two patients were tested for hepatitis B virus (HBV) surface antigen and hepatitis C virus (HCV) core antigen. They provided demographic, medical and dialysis information. Non-compliant behaviors were obtained from their medical records. Overall, 99 % of patients reused their dialyzers and 46 % had arteriovenous fistula on admission. Both HBV and HCV equally accounted for 8 % of patients and concurrent infection accounted for 1 %. Non-compliance rates of dietary and medication were 39 and 27 % respectively. 42 % of patients missed hemodialysis session, 8 % were verbally or physically abusive and 9 % were non-cooperative. Of the 54 % catheterized patients, 7 % improperly cared for their dialysis access. Dietary non-adherence was associated with male patients (p = 0.03) and medication non-adherence was associated with younger age (p = 0.05). Duration between diagnosis of chronic kidney disease and initiation of hemodialysis was associated with improper care of dialysis access (p = 0.04). Time on hemodialysis was associated with missed hemodialysis session (p = 0.007) and verbal or physical abuse (p = 0.01). Health services need to provide safe practice for dialyzer reuse given the endemicity of hepatitis. We believe a national survey similar to ours about seroprevalence and infection control challenges would prepare Vietnam for providing safer satellite treatment units. Safe hemodialysis services should also comprise patient preparedness, education and counseling.

21 CFR 876.5820 - Hemodialysis system and accessories.

Code of Federal Regulations, 2013 CFR

2013-04-01

.... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

21 CFR 876.5820 - Hemodialysis system and accessories.

Code of Federal Regulations, 2011 CFR

2011-04-01

.... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

21 CFR 876.5820 - Hemodialysis system and accessories.

Code of Federal Regulations, 2012 CFR

2012-04-01

.... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

21 CFR 876.5820 - Hemodialysis system and accessories.

Code of Federal Regulations, 2014 CFR

2014-04-01

.... (1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air... conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system...

Role of amyloidosis in determining the prognosis of dialyzed patients with rheumatoid arthritis.

PubMed

Sanai, Toru; Nanishi, Fumio; Nagata, Masatoshi; Hirano, Tadashi; Suematsu, Eiichi; Esaki, Yukio; Miyahara, Hisaaki; Iida, Mitsuo

2007-02-01

The role of secondary amyloidosis in determining the prognosis of dialyzed patients with rheumatoid arthritis (RA) was examined in 22 patients with a mean age of 60.1 years included 21 renal amyloidosis. RA duration until the start of dialysis was 19.5 +/- 7.2 years and the observation period after introduction 27.1 +/- 26.4 months. Of the 14 dead cases, four died due to sepsis, three due to gastrointestinal tract bleeding, two due to congestive heart failure, and eight cases died within 5 months after starting dialysis. When comparing the eight survivors and the nine non-survivors who died within 2 years after the start of dialysis, the former patients showed significantly higher serum albumin, and lower electrocardiogram score and cardiothoracic ratios at the time of introduction to dialysis. The careful prevention and treatment of infection, cerebrovascular and/or gastrointestinal tract complications seem to be necessary to improve the prognosis of RA patients after the initiation of renal replacement therapy.

Detection of small degree of nonuniformity in dialysate flow in hollow-fiber dialyzer using proton magnetic resonance imaging.

PubMed

Osuga, T; Obata, T; Ikehira, H

2004-04-01

A small degree of nonuniformity in dialysate flow in a hollow-fiber dialyzer was detected using proton magnetic resonance imaging (MRI). Since paramagnetic ions reduce the spin-lattice relaxation time of protons around them, MRI can detect Gd in water. An aqueous solution of a chelate compound of Gd was impulsively injected into the dialysate flow path at a flow rate of 500 cm(3) /m, which is that utilized in actual dialysis. Despite the apparent elimination of Gd from the dialysate flow path by the newly injected dialysate fluid after the injection of Gd was terminated, MRI revealed that Gd remained in the interior of the hollow fiber. The observed structure pattern of the Gd concentration profile revealed that the dialysate flow had a small degree of nonuniformity despite the currently established design to restrict channeling in dialysate flow. Local nonuniformity of the hollow-fiber density and vortex generation in the dialysate flow were considered to cause the nonuniformity in the dialysate flow.

Therapeutic plasma exchange performed in tandem with hemodialysis without supplemental calcium in the apheresis circuit.

PubMed

Zhao, Yong; Ibrahim, Hiba; Bailey, Jeffrey A; Linden, Jeanne; Hickson, Elda; Haynes, Stefanie; Greene, Mindy; Vauthrin, Michelle; Weinstein, Robert

2017-06-01

Therapeutic plasma exchange (TPE) and hemopoietic progenitor cell (HPC) collection are apheresis procedures that can safely be performed in tandem with hemodialysis. Despite the return of citrate-anticoagulated blood to the patient during HPC collection, it is not necessary to administer supplemental calcium during these procedures because the ionized calcium concentration is restored as the returning blood passes through the dialyzer. It is not known whether this applies to TPE, in which a mixture of blood and pharmaceutical albumin, an avid binder of plasma ionized calcium, is returned to the patient through the dialyzer. We report on three dialysis-dependent patients who required TPE and underwent tandem treatments without supplemental calcium in the apheresis circuit. Overall, ionized calcium fell 4-12% (P = 0.0.024) and patients reported no symptoms of hypocalcemic toxicity. Tandem hemodialysis/TPE can be performed without supplemental calcium in the apheresis circuit. J. Clin. Apheresis 32:154-157, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Fluorescence measurements of activity associated with a molecularly imprinted polymer imprinted to dipicolinic acid

NASA Astrophysics Data System (ADS)

Anderson, John; Pestov, Dmitry; Fischer, Robert L.; Webb, Stanley; Tepper, Gary C.

2004-03-01

Steady state and lifetime fluorescence measurements were acquired to measure the binding activity associated with molecularly imprinted polymer (MIP) microparticles imprinted to dipicolinic acid. Dipicolinic acid is a unique compound associated with the sporulation phase of spore-forming bacteria (e.g., genus Bacillus and Clostridium). Vinylic monomers were polymerized in a dimethylformamide solution containing the dipicolinic acid as a template. The resulting MIP was then pulverized and size selected into small microscale particles. Samplers were adapted incorporating the MIP particles within a dialyzer (500 MW). Tests were run on replicate samples of biologically active cultures representing both stationary phase and sporulation post fermentation products in standard media. The permeability of the membrane permitted diffusion of lighter molecular weight constituents from media effluents to enter the dialyzer chamber and contact the MIP. Extractions of the media were measured using steady state and lifetime fluorescence. Results showed dramatic steady state fluorescence changes as a function of excitation, emission and intensity and an estimated lifetime of 5.8 ns.

Multilayered microfilter using a nanoporous PES membrane and applicable as the dialyzer of a wearable artificial kidney

NASA Astrophysics Data System (ADS)

Gu, Ye; Miki, Norihisa

2009-06-01

We present a multilayered microfilter for use as a dialyzer of a wearable artificial kidney separating metabolic wastes such as urea, uric acid and creatinine from blood. The microfilter device is assembled by alternately bonding chamber layers made of Ti by wet etching and semipermeable polymeric membranes made of polyethersulfone (PES) by the wet phase inversion method. The PES membranes sandwiched between each two chamber layers act as barriers to molecules larger than 1.7 nm. The multilayered microfilter was geometrically optimized with respect to our theoretical equations and experimental results in order to obtain kidney-competitive performance. Each diffusing unit of our device, which is only 24 × 24 × 0.4 mm3 in size, was proved experimentally to be capable of allowing a flow rate of up to 1 ml min-1 under an input pressure of only 10 kPa, which is the hydrostatic pressure in human renal arteries, while having a urea removal rate of 18 µg min-1.

Multifunctional Nanotherapeutic System for Advanced Prostate Cancer

DTIC Science & Technology

2012-10-01

aqueous part was again dialyzed against fresh deionized water two times for 12 hours. After dialysis the whole content was lyophilized using Freeze ... dryer (VirTis).The conjugate was characterized using UV visible spectroscopy, FT-IR spectroscopy and proton NMR. The results of the UV –Visible

Chemical modification of corn fiber with ion-exchanging groups

USDA-ARS?s Scientific Manuscript database

Pretreated corn fiber was chemically modified with quaternary ammonium group or/and sulfonated with 3-chloro-2-hydroxypropanesulfonic acid under vacuum or at ambient pressure. The soluble fraction was dialyzed through 1 kDa MWCO dialysis tubing and the material retained inside the tubing was filtere...

The clinical evaluation of low-dose heparin in haemodialysis: a prospective study using the heparin-coated AN69 ST membrane.

PubMed

Chanard, Jacques; Lavaud, Sylvie; Maheut, Hervé; Kazes, Isabelle; Vitry, Fabien; Rieu, Philippe

2008-06-01

The AN69 ST haemodialysis membrane, a new membrane resulting from coating polyethyleneimine upon the polyacrylonitrile surface, binds heparin. In patients at risk of bleeding, a pilot study has demonstrated the efficient anticoagulant effect of this heparin-coated membrane. Study design. In chronic haemodialyzed patients, we evaluated whether this anticoagulant effect can be validated in a controlled, prospective, open study. Pragmatically, we tested the hypothesis of no difference of the massive clotting rate in two groups of patients haemodialyzed either with 50% reduced standard doses of nonfractionated heparin using the heparin-coated AN69 ST or with a full dose of heparin (100%) using another type of dialysis membrane that does not bind heparin. Secondary objectives included evaluation of partial clotting, changes in haemoglobin levels, erythropoietin consumption and dialyzer performances. One hundred and eighty-four patients were elected and 170 finally included in an 18-month follow-up study. They were allocated to one of the two arms of the study. In the heparin-reduced group (n = 85, mean age: 73 +/- 11 years), 12 472 sessions were performed after priming the AN69 ST dialyzer with 2 L of heparinized saline (5000 IU/L heparin) and using 50% reduced doses of previously administered heparin. In the control group with standard heparin (n = 85, mean age: 74 +/- 13 years), 14 154 sessions were analysed (NS), and mean heparin doses were 2718 +/- 1388 and 4800 +/- 1564 IU per session, respectively (P < 0.001). In the heparin-reduced group, massive clotting occurred in 1.4 per 1000 sessions, whereas it occurred in 1.6 per 1000 sessions in the standard heparin group (P < 0.05). Mild to moderate partial clotting in the venous drip chamber and in the dialyzer was evaluated in a subset of patients, on a visual scale. It was more frequent in the experimental group than in the control group (P < 0.001). Platelets, haemoglobin levels, erythropoietin needs and dialyzer performances remained unchanged in both groups. The global mean death rate was 16.8% per year and did not differ significantly between groups. The use of the heparin-coated AN69 ST membrane allows a 50% reduction of standard doses of nonfractionated heparin administration for routine haemo- dialysis without increasing the risk of massive clotting of the extracorporeal circuit. This result needs confirmation since massive clotting questions clinical practice and is team dependent.

Properties of an αs-casein-rich casein fraction: influence of dialysis on surface properties, miscibility, and micelle formation.

PubMed

Kessler, Anne; Menéndez-Aguirre, Orquidéa; Hinrichs, Jörg; Stubenrauch, Cosima; Weiss, Jochen

2013-09-01

In this study, the surface tension, miscibility, and particle size distribution of a solution containing an αs-casein (CN)-rich CN fraction (54 wt % αs-CN, 32 wt % β-CN, and 15 wt % κ-CN) were determined at pH 6.6. The nondialyzed CN fraction was compared with a dialyzed one. In the nondialyzed sample, every charge on the protein was compensated by 0.3 charges coming from counterions, whereas in the dialyzed sample, only 0.2 charges could be assigned to each charge on the protein. This relation was determined by calculating the charges at the proteins, taking the measured mineral content into account. The surface tension was measured as a function of the protein concentration by the du Noüy ring method at room temperature. Results indicated alterations in the surface properties after reduction of counterions. The equilibrium surface tension above the critical micelle concentration increased from 40.1×10(-3) to 45×10(-3) N/m, the critical micelle concentration increased from 0.9×10(-4) to 2×10(-3) mol/L, and the minimal area occupied per molecule at the surface increased from 2.4×10(-18) to 4.6×10(-18) m(2). Cloud points were determined by measuring the absorbance of CN solutions as a function of the temperature. The cloud points were found to be concentration dependent and had a minimum at 0.2 wt % at 34°C for nondialyzed CN and at 0.25 wt % at 28°C for dialyzed CN, again demonstrating the influence of counterion reduction. Below the cloud point, a micellar phase was found to exist. The hydrodynamic diameter of the micelles were characterized by dynamic light scattering in both auto- and cross-correlation mode. However, no influence of reduction in counterions could be observed, possibly due to the fact that dynamic light scattering is not a suitable method for this type of system. The presence of self-assembled structures was verified by freeze-fracture electron microscopy. The observed differences between dialyzed and nondialyzed samples were explained by changes in the counterion cloud surrounding the proteins. Consequently, the electrostatic interactions between as well as within the CN are altered by dialysis, which, in turn, affects the behavior at the surface as well as the properties in the solution. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Automated method for study of drug metabolism

NASA Technical Reports Server (NTRS)

Furner, R. L.; Feller, D. D.

1973-01-01

Commercially available equipment can be modified to provide automated system for assaying drug metabolism by continuous flow-through. System includes steps and devices for mixing drug with enzyme and cofactor in the presence of pure oxygen, dialyzing resulting metabolite against buffer, and determining amount of metabolite by colorimetric method.

In silico ordinary differential equation/partial differential equation hemodialysis model estimates methadone removal during dialysis

PubMed Central

Linares, Oscar A; Schiesser, William E; Fudin, Jeffrey; Pham, Thien C; Bettinger, Jeffrey J; Mathew, Roy O; Daly, Annemarie L

2015-01-01

Background There is a need to have a model to study methadone’s losses during hemodialysis to provide informed methadone dose recommendations for the practitioner. Aim To build a one-dimensional (1-D), hollow-fiber geometry, ordinary differential equation (ODE) and partial differential equation (PDE) countercurrent hemodialyzer model (ODE/PDE model). Methodology We conducted a cross-sectional study in silico that evaluated eleven hemodialysis patients. Patients received a ceiling dose of methadone hydrochloride 30 mg/day. Outcome measures included: the total amount of methadone removed during dialysis; methadone’s overall intradialytic mass transfer rate coefficient, km; and, methadone’s removal rate, jME. Each metric was measured at dialysate flow rates of 250 mL/min and 800 mL/min. Results The ODE/PDE model revealed a significant increase in the change of methadone’s mass transfer with increased dialysate flow rate, %Δkm=18.56, P=0.02, N=11. The total amount of methadone mass transferred across the dialyzer membrane with high dialysate flow rate significantly increased (0.042±0.016 versus 0.052±0.019 mg/kg, P=0.02, N=11). This was accompanied by a small significant increase in methadone’s mass transfer rate (0.113±0.002 versus 0.014±0.002 mg/kg/h, P=0.02, N=11). The ODE/PDE model accurately predicted methadone’s removal during dialysis. The absolute value of the prediction errors for methadone’s extraction and throughput were less than 2%. Conclusion ODE/PDE modeling of methadone’s hemodialysis is a new approach to study methadone’s removal, in particular, and opioid removal, in general, in patients with end-stage renal disease on hemodialysis. ODE/PDE modeling accurately quantified the fundamental phenomena of methadone’s mass transfer during hemodialysis. This methodology may lead to development of optimally designed intradialytic opioid treatment protocols, and allow dynamic monitoring of outflow plasma opioid concentrations for model predictive control during dialysis in humans. PMID:26229501

Vitamin E-coated membrane dialyzer and beta2-microglobulin removal.

PubMed

Mandolfo, S; Bucci, R; Imbasciati, E

2003-12-01

This study was designed to test the removal of beta2-microglobulin (beta2M) in a vitamin E-modified membrane. We investigated in vivo the dialyzer (Excebrane, series EE, 1.8 m2) with respect to hydraulic permeability (Kuf), maximum ultrafiltration rate (UF max), sieving coefficient (Sc), and solute clearances in hemodialysis (HD) and in soft hemodiafiltration (HDF). Kuf was 18.4 ml/h/mmHg, UF max was 75 ml/min, and Sc for beta2M was 0.45. Clearance values at 400 ml/min of Qb in HD were 258 ml/min for urea, 201 ml/min for creatinine, and 135 ml/min for phosphate. In soft HDF, clearances were slightly higher. beta2M clearance was 26 ml/min in HD and 43 ml/min in soft HDF. In conclusion, Excebrane (series EE) procures a soft HDF with an amount of substitution fluid in post dilution mode of over 60 ml/min. Remarkable small solute clearances were obtained when the blood flow was raised to 400 ml/min. A significant reduction of beta2M is demonstrated by HDF.

Iron, zinc and calcium dialyzability from extruded product based on whole grain amaranth (Amaranthus caudatus and Amaranthus cruentus) and amaranth/Zea mays blends.

PubMed

Galan, María Gimena; Drago, Silvina Rosa; Armada, Margarita; José, Rolando González

2013-06-01

Amaranth is a Native American grain appreciated for its high nutritional properties including high mineral content. The aim of this study was to evaluate the availability of Fe, Zn and Ca from extruded products made with two varieties of amaranth and their mixtures with maize at two levels of replacement. Mineral availability was estimated using dialyzability method. The contents of Fe (64.0-84.0 mg/kg), Ca (1977.5-2348.8 mg/kg) and Zn (30.0-32.1 mg/kg) were higher in amaranth than in maize products (6.2, 19.1, 9.7 mg/kg, respectively). Mineral availability was in the range of (2.0-3.6%), (3.3-11.1%) and (1.6-11.4%) for Fe, Ca and Zn, respectively. Extruded amaranth and amaranth/maize products provide higher amount of Fe and Ca than extruded maize. Extruded amaranth products and amaranth addition to maize could be an interesting way to increase nutritional value of extruded products.

Solute solver 'what if' module for modeling urea kinetics.

PubMed

Daugirdas, John T

2016-11-01

The publicly available Solute Solver module allows calculation of a variety of two-pool urea kinetic measures of dialysis adequacy using pre- and postdialysis plasma urea and estimated dialyzer clearance or estimated urea distribution volumes as inputs. However, the existing program does not have a 'what if' module, which would estimate the plasma urea values as well as commonly used measures of hemodialysis adequacy for a patient with a given urea distribution volume and urea nitrogen generation rate dialyzed according to a particular dialysis schedule. Conventional variable extracellular volume 2-pool urea kinetic equations were used. A javascript-HTML Web form was created that can be used on any personal computer equipped with internet browsing software, to compute commonly used Kt/V-based measures of hemodialysis adequacy for patients with differing amounts of residual kidney function and following a variety of treatment schedules. The completed Web form calculator may be particularly useful in computing equivalent continuous clearances for incremental hemodialysis strategies. © The Author 2016. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Serum cardiac troponin T and effective blood flow in stable extracorporeal dialysis patients.

PubMed

Grzegorzewska, Alicja E; Cieszyński, Krzysztof; Niepolski, Leszek; Kaczmarek, Andrzej; Sowińska, Anna

2016-03-01

We examined the association between extracorporeal dialysis (ED)-related effective blood flow (eQB) and serum cardiac troponin T (cTnT) as a possible indicator of silent myocardial damage in stable ED patients. In a cross-sectional study, cTnT was determined in 247 ED patients dialyzed using stable eQB and dialysate flow (QD). In a prospective study, 91 patients were switched from low-flux (LF) to high-flux (HF) hemodialysis (HD), and subsequently, the eQB increased, and the QD decreased; 65 patients continued LF-HD with stable eQB and QD. Clinical/laboratory evaluations were performed at 0, 15, 36, and 53 weeks from the start of the study. In the cross-sectional study, the main cTnT predictors were dialysis vintage, age, eQB, phosphorus, and C-reactive protein. Patients with cTnT levels in the highest quartile were excluded from the analysis, and subjects dialyzed with eQB ≤316 ml/min exhibited lower cTnT levels compared with patients dialyzed with higher eQB (P = 0.002). The all-cause and cardiac mortality rates of 154 patients, without changes in ED modality for up to 42 months, were associated with the initial cTnT concentrations but not with the initial eQB. In the prospective study, higher values for eQB and cTnT were observed during HF-HD at weeks 36 (P = 0.045) and 53 (P = 0.01) of the present study. The initial cTnT, ∆eQB, and ∆albumin influenced the ∆cTnT. The all-cause and cardiac mortality rates were not different between LF and HF groups at 21 months after the prospective study was completed. In stable ED patients, higher eQB rates and QB/QD values might contribute to silent myocardial injury, particularly in patients with lower cTnT levels, but do not affect the outcome of ED patients.

Comparison of the Impact of High-Flux Dialysis on Mortality in Hemodialysis Patients with and without Residual Renal Function

PubMed Central

Kim, Hyung Wook; Kim, Su-Hyun; Kim, Young Ok; Jin, Dong Chan; Song, Ho Chul; Choi, Euy Jin; Kim, Yong-Lim; Kim, Yon-Su; Kang, Shin-Wook; Kim, Nam-Ho; Yang, Chul Woo; Kim, Yong Kyun

2014-01-01

Background The effect of flux membranes on mortality in hemodialysis (HD) patients is controversial. Residual renal function (RRF) has shown to not only be as a predictor of mortality but also a contributor to β2-microglobulin clearance in HD patients. Our study aimed to determine the interaction of residual renal function with dialyzer membrane flux on mortality in HD patients. Methods HD Patients were included from the Clinical Research Center registry for End Stage Renal Disease, a prospective observational cohort study in Korea. Cox proportional hazards regression models were used to study the association between use of high-flux dialysis membranes and all-cause mortality with RRF and without RRF. The primary outcome was all-cause mortality. Results This study included 893 patients with 24 h-residual urine volume ≥100 ml (569 and 324 dialyzed using low-flux and high-flux dialysis membranes, respectively) and 913 patients with 24 h-residual urine volume <100 ml (570 and 343 dialyzed using low-flux and high-flux dialysis membranes, respectively). After a median follow-up period of 31 months, mortality was not significantly different between the high and low-flux groups in patients with 24 h-residual urine volume ≥100 ml (HR 0.86, 95% CI, 0.38–1.95, P = 0.723). In patients with 24 h-residual urine volume <100 ml, HD using high-flux dialysis membrane was associated with decreased mortality compared to HD using low-flux dialysis membrane in multivariate analysis (HR 0.40, 95% CI, 0.21–0.78, P = 0.007). Conclusions Our data showed that HD using high-flux dialysis membranes had a survival benefit in patients with 24 h-residual urine volume <100 ml, but not in patients with 24 h-residual urine volume ≥100 ml. These findings suggest that high-flux dialysis rather than low-flux dialysis might be considered in HD patients without RRF. PMID:24906205

Nutritional status in stage V dialyzed patient versus CKD patient on conservative therapy across different economic status.

PubMed

Vijayan, Madhusudan; Abraham, Georgi; Alex, Merina E; Vijayshree, N; Reddy, Yuvaram; Fernando, Edwin; Mathew, Milly; Nair, Sanjeev; Yuvaraj, Anand

2014-04-01

This aim of this multi-centric cross-sectional study was to assess the nutritional status in Indian chronic kidney disease (CKD) patients and to compare the nutritional indicators between stage 5 dialyzed (CKD-D) patients below the poverty line (BPL), and stage 3-4 non-dialyzed (CKD-ND) patients above (APL) and below the poverty line. Patients were selected from a government medical college hospital, a charity-based outpatient dialysis unit, and a non-profit tertiary care center. The study groups included BPL CKD-ND (n = 100), BPL CKD-D (n = 98), and APL CKD-ND (n = 92) patients, based on a cut-off of per capita income US $1.25 a day. Patients were enquired by a qualified renal dietitian about their pattern of diet, and daily energy and protein intake by 24 h recall method. Anthropometric measurements and biochemical investigations were made and compared. Nutritional indicators were low in all three groups compared to those prescribed by European Best Practice Guidelines (EBPG). BPL CKD-D patients had low serum albumin levels (32.44444 ± 6.279961 g/L; p = 0.017) and 41.83% of them were underweight. The APL CKD-ND group registered the lowest mean daily energy (22.576 ± 6.289 kcal/kg/day) and protein intake (0.71 ± 0.06 g/kg/day), due to dietary restrictions imposed on them by themselves and unqualified renal dietitians. The APL group had better indicators of nutritional status in terms of mid-upper arm circumference (p = 0.001), triceps skin fold thickness (p < 0.001), and serum hemoglobin (p < 0.001). Several nutritional parameters were below the recommended international guidelines for all the three groups, though the high income group had better parameters from several indicators. There is an urgent need for nutritional counseling for CKD-D and CKD-ND patients.

Determination of VIT 45 (IND#63,243 - American Regent) removal by closed loop in vitro hemodialysis system.

PubMed

Manley, H J; McClaran, M L

2006-11-01

Intravenous iron is typically administered during the hemodialysis (HD) procedure. The extent of VIT 45, a novel intravenous iron formulation, removal by high-flux (HF) or high-efficiency (HE) dialysis membranes at various ultrafiltration rates (UFR) is unknown. An in vitro HD system was constructed to determine the dialyzability of iron from a normal saline compartment (NSC) containing 1000 mg iron of VIT 45. The in vitro system utilized a 6-L closed-loop SBS system that was subject to 4 different HD conditions conducted over 4 hours: HE membrane + 0 ml/h UFR; HE membrane + 500 ml/h UFR; HF membrane + 0 ml/h UFR; HF membrane + 500 ml/h UFR. Blood flow and dialysate flow rates were 500 ml/min and 800 ml/min, respectively. The dialysate compartment was a 6-L closed-loop system. A volumetric HD machine controlled all blood, dialysate, and ultrafiltration rates. NSC and dialysate compartment samples were taken at various time points and iron elimination rate (khd) and HD clearance (Clhd) was determined. Iron removal from the NSC > 15% was considered clinically significant. The percent removal of iron from the NSC was < 0.5% at all time points in the study. Dialysate recovery of iron was negligible: 1.7-5.1 mg. VIT 45 removal elimination rates from NSC were less than -0.001 h(-1) (range -0.0002 +/- 0.0001 to -0.0001 +/- 0.0002 h (-1)) for all study conditions. Dialyzer type or UFR did not effect iron removal. HF or HE dialysis membranes do not remove clinically significant amounts of VIT 45 over a 4-hour in vitro HD session. This effect remained constant even controlling for UFR up to 500 ml/hour. VIT 45 is not dialyzed by HE or HF dialysis membranes irrespective of UFR.

Effect of High-Cutoff Hemodialysis vs Conventional Hemodialysis on Hemodialysis Independence Among Patients With Myeloma Cast Nephropathy: A Randomized Clinical Trial.

PubMed

Bridoux, Frank; Carron, Pierre-Louis; Pegourie, Brigitte; Alamartine, Eric; Augeul-Meunier, Karine; Karras, Alexandre; Joly, Bertrand; Peraldi, Marie-Noëlle; Arnulf, Bertrand; Vigneau, Cécile; Lamy, Thierry; Wynckel, Alain; Kolb, Brigitte; Royer, Bruno; Rabot, Nolwenn; Benboubker, Lotfi; Combe, Christian; Jaccard, Arnaud; Moulin, Bruno; Knebelmann, Bertrand; Chevret, Sylvie; Fermand, Jean-Paul

2017-12-05

Cast nephropathy is the main cause of acute kidney injury in multiple myeloma and persistent reduction in kidney function strongly affects prognosis. Strategies to rapidly remove nephrotoxic serum-free light chains combined with novel antimyeloma agents have not been evaluated prospectively. To compare the hemodialysis independence rate among patients newly diagnosed with myeloma cast nephropathy treated with hemodialysis using a high-cutoff dialyzer (with very large membrane pores and high permeability to immunoglobulin light chains) or a conventional high-flux dialyzer (with small pores and lower permeability). Randomized clinical trial involving 98 patients with biopsy-proven myeloma cast nephropathy requiring hemodialysis treated at 48 French centers between July 2011 and June 2016; the final date of follow-up was June 29, 2016. Intensive hemodialysis (eight 5-hour sessions over 10 days) with either a high-cutoff dialyzer (46 patients) or a conventional high-flux dialyzer (48 patients). All patients received the same chemotherapy regimen of bortezomib and dexamethasone. Primary end point was hemodialysis independence at 3 months; secondary end points: hemodialysis independence rates at 6 and 12 months, hemodialysis- and chemotherapy-related adverse events, and death. Among 98 randomized patients, 94 (96%) (median age, 68.8 years [interquartile range, 61.2-75.3 years]; 45% women) were included in the modified intent-to-treat analysis. The hemodialysis independence rate at 3 months was 41.3% (n = 19) in the high-cutoff hemodialysis group vs 33.3% (n = 16) in the conventional hemodialysis group (between-group difference, 8.0% [95% CI, -12.0% to 27.9%], P = .42); at 6 months, the rate was 56.5% (n = 26) vs 35.4% (n = 17), respectively (between-group difference, 21.1% [95% CI, 0.9% to 41.3%], P = .04); and at 12 months, the rate was 60.9% (n = 28) vs 37.5% (n = 18) (between-group difference, 23.4% [95% CI, 3.2% to 43.5%], P = .02). The incidence of hemodialysis-related adverse events was 43% in the high-cutoff hemodialysis group vs 39% in the conventional hemodialysis group; chemotherapy-related serious adverse events, 39% vs 37%, respectively; and at 12 months, 9 patients vs 10 patients died. Among patients with myeloma cast nephropathy treated with a bortezomib-based chemotherapy regimen, the use of high-cutoff hemodialysis compared with conventional hemodialysis did not result in a statistically significant difference in hemodialysis independence at 3 months. However, the study may have been underpowered to identify an early clinically important difference. clinicaltrials.gov Identifier: NCT01208818.

Milk peptides increase iron solubility in water but do not affect DMT-1 expression in Caco-2 cells

USDA-ARS?s Scientific Manuscript database

In vitro digestion of milk produces peptide fractions that enhance iron uptake by Caco-2 cells. Our objectives were to investigate whether these fractions a) exert their effect by increasing relative gene expression of DMT-1 in Caco-2 cells b) enhance iron dialyzability when added in meals. Peptid...

Cell activation and cellular-cellular interactions during hemodialysis: effect of dialyzer membrane.

PubMed

Sirolli, V; Ballone, E; Di Stante, S; Amoroso, L; Bonomini, M

2002-06-01

During hemodialysis (HD), circulating blood cells can be activated and also engage in dynamic interplay. These phenomena may be important factors behind dialysis membrane bio(in)compatibility. In the present prospective cross-over study, we have used flow cytometry to evaluate the influence of different dialysis membranes on the activation of circulating blood cells (leukocytes, platelets) and their dynamic interactions (formation of circulating platelet-leukocyte and platelet-erythrocyte aggregates) during in vivo HD. Each patient (n = 10) was treated with dialyzers containing membranes of cellulose diacetate, polysulfone and ethylenevinylalcohol (EVAL) in a randomized order. Upregulation of adhesion receptor expression (CD15s, CD11b/CD18) occurred mainly with the cellulosic membrane, though an increase in CD11b/CD18 circulating on neutrophils was also found with both synthetic membranes. Circulating activated platelets (P-selectin/CD63-positive platelets) increased during HD sessions with cellulose diacetate and polysulfone. An increased formation of platelet-neutrophil aggregates was found at 15 and 30 min during dialysis with cellulose diacetate and polysulfone but not with EVAL. Platelet-erythrocyte aggregates also increased with cellulose diacetate and at 15 min with polysulfone as well. Generally in concomitance with the increase in platelet-neutrophil coaggregates, there was an increased hydrogen peroxide production by neutrophils. The results of this study indicate that cellular mechanisms can be activated during HD largely depending on the membrane material, EVAL causing less reactivity than the other two membranes. It appears that each dialysis membrane has multiple and different characteristics that may contribute to interactions with blood components. Our results also indicate that derivatizing cellulose (cellulose diacetate) may be a useful way to improve the biocompatibility of the cellulose polymer and that there may be great variability in the biocompatibility profile of synthetic membranes, dialysis with polysulfone being in general associated with a higher degree of cell activation than EVAL membrane.

Effect of selected solutes on growth and recovery of a radiation-resistant Moraxella

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruns, M.A.; Maxcy, R.B.

1978-01-01

A highly radiation-resistant Moraxella sp. from beef was more resistant to gamma radiation in frozen beef than Clostridium botulinum 33A spores. Even though the Moraxella sp. was extremely radiation-resistant, its recovery after irradiation was markedly influenced by the plating medium. Fewer colony-forming units were recovered in Tryptic Soy Agar (TSA) than in Plate Count Agar (PCA), and differences in recovery became more pronounced with increasing radiation dose. Growth studies of the nonirradiated Moraxella sp. suggested the presence of dialyzable inhibitory factor(s) in Trypticase Soy Broth (TSB) and TSA. The low (0.5 percent) concentration of NaCl in TSA was shown tomore » be mainly responsible for the slow growth and reduced recovery after irradiation. Reduced recovery was also obtained by plating the Moraxella sp. in PCA plus 0.5 percent NaCl or PCA plus 6 percent glucose after irradiation. It was noted that 2 other highly radiation-resistant isolates identified as Moraxella sp. gave similar results. Sensitivity to low solute concentrations, therefore, appeared to be a general phenomenon for this group.« less

Application of in vitro bioaccessibility and bioavailability methods for calcium, carotenoids, folate, iron, magnesium, polyphenols, zinc and vitamins B6, B12, D, and E

USDA-ARS?s Scientific Manuscript database

A review of in vitro bioaccessibility and bioavailability methods for polyphenols and selected nutrients is presented. The review focuses on in vitro solubility, dialyzability, the dynamic gastrointestinal model (TIM), and Caco-2 cell models, the latter primarily for uptake and transport, and a disc...

Mid-dilution hemodiafiltration: a comparison with pre- and postdilution modes using the same polyphenylene membrane.

PubMed

Maduell, Francisco; Arias, Marta; Vera, Manel; Fontseré, Néstor; Blasco, Miquel; Barros, Xoana; Garro, Julia; Elena, Montserrat; Bergadá, Eduardo; Cases, Aleix; Bedini, Jose Luis; Campistol, Josep M

2009-01-01

As a change from Diapes to polyphenylene membrane in the mid-dilution filter has recently been developed, the aim of this study was to compare mid-dilution using this new dialyzer versus pre- and postdilution. The prospective study included 20 patients who underwent 4 hemodiafiltration (HDF) sessions: 1.7 m(2) polyphenylene and predilution infusion flow (Qi) 200 ml/min, 1.7 m(2) and postdilution Qi 100 ml/min, 1.9 and 2.2 m(2) mid-dilution both with Qi 200 ml/ min. The urea and creatinine reduction ratios were slightly higher in postdilution. The beta(2)-microglobulin (85.8%), myoglobin (73.6%), prolactin (67.8%) and retinol-binding protein (29.2%) reduction ratios with 1.9 m(2) mid-dilution, which was similar to 2.2 m(2) mid-dilution, were significantly higher than with the post- and predilution modes. Mid-dilution appears to be a good HDF alternative that allows a better removal of larger molecules than postdilution and, mainly, predilution. Mid-dilution using 1.9 or 2.2 m(2) dialyzers, at the same convective volume, showed a similar removal. Copyright 2009 S. Karger AG, Basel.

Anti-Inflammatory Effect of Dialyzable Leukocyte Extract in Autoimmune Prostatitis: Evaluation in Animal Model

PubMed Central

Pérez-Alvarado, Carlos; Gómez, Consuelo; Reyes, Miguel; García, Mario; Pérez, Elizabeth; Pérez de la Mora, Carlos; Sanchez, Virginia

2017-01-01

Objective. To evaluate the anti-inflammatory properties of Dialyzable Leukocyte Extract (DLE) in a murine model of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Methods. Histopathological characterization, prostatein Enzyme-Linked Immunosorbent Assay, and immunohistochemical analysis for CD45, TNF-α, IFN-γ, IL-6, IL-17, and IL-4 molecules were done in prostatic Wistar rats treated with DLE, placebo, or Dexamethasone. Results. Histopathological analysis of animals induced to prostatitis showed inflammatory infiltrate, mainly constituted by leucocytes and mast cells as well as Benign Prostatic Hyperplasia. Serum prostatein concentrations were 14 times higher than those displayed by healthy animals. After DLE and Dexamethasone treatments, the inflammatory infiltrate decreased; the tissue morphology was similar to that of a normal prostate, and the prostatein decreased to the basal levels of healthy animals. DLE treatment produced a decreased expression of the cell surface marker CD45 and the proinflammatory cytokines TNF-α, IFN-γ, IL-6, and IL-17. On the other hand, the expression of anti-inflammatory cytokine IL-4 increased in both the Dexamethasone and DLE groups. Conclusion. DLE is able to modulate the inflammatory response in Experimental Autoimmune Prostatitis (EAP). PMID:28386549

Retrospective study of salazosulfapyridine in eight patients with rheumatoid arthritis on hemodialysis.

PubMed

Akiyama, Yuji; Sakurai, Yusei; Kato, Yuji; Furuta, Eiichi; Mimura, Toshihide

2014-03-01

We examined the pharmacokinetics (PK) of salazosulfapyridine (SASP) and its metabolite, sulfapyridine (SP), as well as the influence of hemodialysis (HD), and investigated the utility of consecutive administration of SASP in rheumatoid arthritis patients undergoing HD. The PK of salazosulfapyridine and SP in serum samples from 8 patients was determined using high-performance liquid chromatography. When SASP 500 mg was administered, the area under curve for serum concentration of SASP was similar to that seen with normal subjects in the Phase I study. The maximum serum concentration of SP was significantly higher than that in normal subjects, but was far from the danger level. SASP was not dialyzed, whereas on average 62% of SP was dialyzed. Following 5 consecutive days of administration of SASP, serum levels of SASP and SP on day 5 were rather higher than those on day 1, although both remained within the safe range. SASP administration from four months to three years in seven subjects resulted in four American College of Rheumatology 20 improvement criteria (57.1%), with one developing a rash. If SASP is initiated at a low dosage (≤ 500 mg) and increased up to 1000 mg under careful monitoring, it is safe for HD patients.

Pharmacokinetic modeling of 4,4'-methylenedianiline released from reused polyurethane dialyzer potting materials.

PubMed

Do Luu, H M; Hutter, J C

2000-01-01

4, 4'-Methylenedianiline (MDA) is a hydrolysis degradation product that can be released from polyurethanes commonly used in medical device applications. MDA is mutagenic and carcinogenic in animals. In humans, it is hepatotoxic, a known contact and respiratory allergen, and a suspected carcinogen. A physiologically based pharmacokinetic (PBPK) model was developed to estimate the absorption, distribution, metabolism, and excretion of MDA in patients exposed to MDA leached from the potting materials of hemodialyzers. A worst-case reuse situation and a single use case were investigated. The PBPK model included five tissue compartments: liver, kidney, gastrointestinal tract, slowly perfused tissues, and richly perfused tissues. Physiological and chemical parameters of a healthy individual used in the model were obtained from the literature. The model was calibrated using previously published kinetic studies of IV administered doses of (14) C-MDA to rats. The model was validated using independent data published for MDA-exposed workers. The PBPK results indicated that dialysis patients who are exposed to MDA released from dialyzers (new or reused) could accumulate low levels of MDA and metabolites (total MDA) over time. Copyright 2000 John Wiley & Sons, Inc.

In Vivo Chemoprotective Activity of Bovine Dialyzable Leukocyte Extract in Mouse Bone Marrow Cells against Damage Induced by 5-Fluorouracil

PubMed Central

Coronado-Cerda, Erika Evangelina; Franco-Molina, Moisés Armides; Mendoza-Gamboa, Edgar; Prado-García, Heriberto; Rivera-Morales, Lydia Guadalupe; Zapata-Benavides, Pablo; Rodríguez-Salazar, María del Carmen; Caballero-Hernandez, Diana; Tamez-Guerra, Reyes Silvestre; Rodríguez-Padilla, Cristina

2016-01-01

Chemotherapy treatments induce a number of side effects, such as leukopenia neutropenia, peripheral erythropenia, and thrombocytopenia, affecting the quality of life for cancer patients. 5-Fluorouracil (5-FU) is wieldy used as myeloablative model in mice. The bovine dialyzable leukocyte extract (bDLE) or IMMUNEPOTENT CRP® (ICRP) is an immunomodulatory compound that has antioxidants and anti-inflammatory effects. In order to investigate the chemoprotection effect of ICRP on bone marrow cells in 5-FU treated mice, total bone marrow (BM) cell count, bone marrow colony forming units-granulocyte/macrophage (CFU-GM), cell cycle, immunophenotypification, ROS/superoxide and Nrf2 by flow cytometry, and histological and hematological analyses were performed. Our results demonstrated that ICRP increased BM cell count and CFU-GM number, arrested BM cells in G0/G1 phase, increased the percentage of leukocyte, granulocytic, and erythroid populations, reduced ROS/superoxide formation and Nrf2 activation, and also improved hematological levels and weight gain in 5-FU treated mice. These results suggest that ICRP has a chemoprotective effect against 5-FU in BM cells that can be used in cancer patients. PMID:27191003

Anti-Inflammatory Effect of Dialyzable Leukocyte Extract in Autoimmune Prostatitis: Evaluation in Animal Model.

PubMed

Pérez-Alvarado, Carlos; Gómez, Consuelo; Reyes, Miguel; García, Mario; Pérez, Elizabeth; Pérez de la Mora, Carlos; Sanchez, Virginia; Pérez Ishiwara, D Guillermo

2017-01-01

Objective. To evaluate the anti-inflammatory properties of Dialyzable Leukocyte Extract (DLE) in a murine model of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Methods. Histopathological characterization, prostatein Enzyme-Linked Immunosorbent Assay, and immunohistochemical analysis for CD45, TNF- α , IFN- γ , IL-6, IL-17, and IL-4 molecules were done in prostatic Wistar rats treated with DLE, placebo, or Dexamethasone. Results. Histopathological analysis of animals induced to prostatitis showed inflammatory infiltrate, mainly constituted by leucocytes and mast cells as well as Benign Prostatic Hyperplasia. Serum prostatein concentrations were 14 times higher than those displayed by healthy animals. After DLE and Dexamethasone treatments, the inflammatory infiltrate decreased; the tissue morphology was similar to that of a normal prostate, and the prostatein decreased to the basal levels of healthy animals. DLE treatment produced a decreased expression of the cell surface marker CD45 and the proinflammatory cytokines TNF- α , IFN- γ , IL-6, and IL-17. On the other hand, the expression of anti-inflammatory cytokine IL-4 increased in both the Dexamethasone and DLE groups. Conclusion. DLE is able to modulate the inflammatory response in Experimental Autoimmune Prostatitis (EAP).

Relation between serum creatinine and postoperative results of open-heart surgery.

PubMed

Ezeldin, Tamer H

2013-10-01

To determine the impact of preoperative serum creatinine level in non-dialyzable patients on postoperative morbidity and mortality. This is a prospective study, where serum creatinine was used to give primary assessment on renal function status preoperatively. This study includes 1,033 patients, who underwent coronary artery bypass grafting, or valve(s) operations. The study took place at Al-Hada Military Hospital, Taif, Kingdom of Saudi between May 2008 and January 2012. Data were statistically analyzed using Chi square (x2) test and multivariable logistic regression, to evaluate the postoperative morbidity and mortality risks associated with low serum creatinine levels. Postoperative mortality increased with high serum creatinine level >1.8 mg/dL (p

Food matrix and cooking process affect mineral bioaccessibility of enteral nutrition formulas.

PubMed

Galán, María Gimena; Drago, Silvina Rosa

2014-02-01

When enteral formulas (EF) are administered orally as a supplement to the normal diet, they are often mixed with conventional foods or included in recipes in order to seek new flavors and textures and avoid monotony. The aims of this work were to study the bioaccessibility of Fe, Zn and Ca from commercial EF and the impact upon their incorporation into sweet preparations. Twenty commercial EF, before and after inclusion in sweet food (rice pudding, RP; banana smoothie, BS; tea, T; chocolate dessert, CD) were evaluated regarding Fe, Zn and Ca dialyzability (%DFe , %DZn , %DCa ) as an estimator of mineral bioaccessibility. Fe, Zn and Ca dialyzability from EF was variable and generally low. Heating during EF-sweet food preparation (T and CD) lowered values to 44.1 %DFe , possibly due to degradation of vitamin C, and 52.7 %DZn and 25.3 %DCa , due to the interaction with food components. EF and EF-sweet foods did not represent a good supply of Fe, Zn and Ca as recommended. This study demonstrated how the bioaccessibility of these minerals is affected by the food matrix in which EF is included as well as heating during food preparation. © 2013 Society of Chemical Industry.

Phosphate removal and hemodialysis conditions.

PubMed

Pohlmeier, R; Vienken, J

2001-02-01

Hyperphosphatemia is frequently found in hemodialysis patients, and the association with an increased risk of mortality has been demonstrated. Other authors have linked hyperphosphatemia to increased cardiovascular mortality. The normalization of phosphate plasma levels is therefore an important goal in the treatment of end-stage renal disease patients. Absorption of phosphate from the food exceeds the elimination through a hemodialysis treatment, and this leads to a chronic phosphate load for the majority of hemodialysis patients. This imbalance should be improved by either a reduction of phosphate absorption or an increased removal of phosphate. A reduction of phosphate absorption can be achieved by reducing the amount of phosphate in the diet or by the administration of phosphate binders. Unfortunately, these measures imply practical difficulties, for example, a lack of patient compliance or other side effects. When considering modifications of the hemodialysis treatment, an essential understanding of the kinetics of dialytic phosphate removal is mandatory. Phosphate is unevenly distributed in different compartments of the body. Only a very small amount of phosphate is present in the easily accessible plasma compartment. The major part of phosphate removed during hemodialysis originates from the cytoplasm of cells. A transfer from intracellular space to the plasma and further from the plasma to the dialysate is necessary. However, if we consider improvement to phosphate removal by dialysis procedures, full dialyzer clearance is effective in only the initial phase of the dialysis treatment. After this initial phase, the transfer rate for phosphate from the intracellular space to the plasma becomes the rate-limiting step for phosphate transport. Attempts to improve this transfer rate have recently been investigated by acidosis correction, but turned out not to be consistently successful. Furthermore, modifications of the treatment schedule have been described in the literature as measures to influence the phosphate balance consistently. Successful improvements of the phosphate balance can be achieved specifically through increasing the frequency of the dialysis treatments.

Japan Report, Science and Technology.

DTIC Science & Technology

1987-04-28

manufacture liquid hydrogen domestically because "a method to manufacture hydrogen by decomposing methanol is in commercial use and if we neglect this area...system or element, and how safety is related to materials, production methods , and sterilization. The environment where the materials are used...be essential to produce them in a clean environment. For instance, the dialyzer-sterilizing method is changing. Initially, it was sold in

Substrate Dependence in the Growth of Three-Dimensional Gold Nanoparticle Superlattices

DTIC Science & Technology

2001-11-01

the Hamaker constants between gold nanoparticle assemblies and substrates through the suspension. Van der Waals interactions estimated from this...finally dialyzed to remove inorganic (Na, Cl, and B) and organic impurities. The surfactant affects the dispersion of Au nanoparticles in aqueous...be taken into account for complete understanding of the observed substrate dependency. To consider volume interactions, we calculate the Hamaker

The Effects of Super-Flux (High Performance) Dialyzer on Plasma Glycosylated Pro-B-Type Natriuretic Peptide (proBNP) and Glycosylated N-Terminal proBNP in End-Stage Renal Disease Patients on Dialysis

PubMed Central

Nakagawa, Yasuaki; Nishikimi, Toshio; Kuwahara, Koichiro; Yasuno, Shinji; Kinoshita, Hideyuki; Kuwabara, Yoshihiro; Nakao, Kazuhiro; Minami, Takeya; Yamada, Chinatsu; Ueshima, Kenji; Ikeda, Yoshihiro; Okamoto, Hiroyuki; Horii, Kazukiyo; Nagata, Kiyoshi; Kangawa, Kenji; Minamino, Naoto; Nakao, Kazuwa

2014-01-01

Background Plasma BNP levels are predictive of prognosis in hemodialysis patients. However, recent studies showed that the current BNP immunoassay cross-reacts with glycosylated proBNP, and the NT-proBNP assay underestimates glycosylated NT-proBNP. In addition, the recently developed high performance dialyzer removes medium-sized molecular solutes such as β2-microgloburin. We therefore investigated the effects of high performance dialysis on measured levels of glycosylated proBNP, glycosylated NT-proBNP and other BNP-related peptides in end-stage renal disease (ESRD) patients on hemodialysis. Method The relationships between clinical parameters and BNP-related molecule were also investigated. We used our newly developed immunoassay to measure plasma total BNP and proBNP in 105 normal subjects and 36 ESRD patients before and after hemodialysis. Plasma NT-proBNP was measured using Elecsys II after treatment with or without deglycosylating enzymes. We also measured plasma ANP and cGMP using radioimmunoassays. Results All the measured BNP-related peptides were significantly higher in ESRD patients than healthy subjects. Total BNP (−38.9%), proBNP (−29.7%), glycoNT-proBNP (−45.5%), nonglycoNT-proBNP (−53.4%), ANP (−50.4%) and cGMP (−72.1%) were all significantly reduced after hemodialysis, and the magnitude of the reduction appeared molecular weight- dependent. Both the proBNP/total BNP and glycoNT-proBNP/nonglycoNT-proBNP ratios were increased after hemodialysis. The former correlated positively with hemodialysis vintage and negatively with systolic blood pressure, while the latter correlated positively with parathyroid hormone levels. Conclusion These results suggest that hemodialysis using super-flux dialyzer removes BNP-related peptides in a nearly molecular weight-dependent manner. The ProBNP/total BNP and glycoNT-proBNP/nonglycoNT-proBNP ratios appear to be influenced by hemodialysis-related parameters in ESRD patients on hemodialysis. PMID:24667631

State-dependent and -independent effects of dialyzing excitatory neuromodulator receptor antagonists into the ventral respiratory column

PubMed Central

Langer, Thomas M.; Neumueller, Suzanne E.; Crumley, Emma; Burgraff, Nicholas J.; Talwar, Sawan; Hodges, Matthew R.; Pan, Lawrence

2017-01-01

Unilateral dialysis of the broad-spectrum muscarinic receptor antagonist atropine (50 mM) into the ventral respiratory column [(VRC) including the pre-Bötzinger complex region] of awake goats increased pulmonary ventilation (V̇i) and breathing frequency (f), conceivably due to local compensatory increases in serotonin (5-HT) and substance P (SP) measured in effluent mock cerebral spinal fluid (mCSF). In contrast, unilateral dialysis of a triple cocktail of antagonists to muscarinic (atropine; 5 mM), neurokinin-1, and 5-HT receptors does not alter V̇i or f, but increases local SP. Herein, we tested hypotheses that 1) local compensatory 5-HT and SP responses to 50 mM atropine dialyzed into the VRC of goats will not differ between anesthetized and awake states; and 2) bilateral dialysis of the triple cocktail of antagonists into the VRC of awake goats will not alter V̇i or f, but will increase local excitatory neuromodulators. Through microtubules implanted into the VRC of goats, probes were inserted to dialyze mCSF alone (time control), 50 mM atropine, or the triple cocktail of antagonists. We found 1) equivalent increases in local 5-HT and SP with 50 mM atropine dialysis during wakefulness compared with isoflurane anesthesia, but V̇i and f only increased while awake; and 2) dialyses of the triple cocktail of antagonists increased V̇i, f, 5-HT, and SP (<0.05) during both day and night studies. We conclude that the mechanisms governing local neuromodulator levels are state independent, and that bilateral excitatory receptor blockade elicits an increase in breathing, presumably due to a local, (over)compensatory neuromodulator response. NEW & NOTEWORTHY The two major findings are as follows: 1) during unilateral dialysis of 50 mM atropine into the ventral respiratory column to block excitatory muscarinic receptor activity, a compensatory increase in other neuromodulators was state independent, but the ventilatory response appears to be state dependent; and 2) the hypothesis that absence of decreased V̇i and f during unilateral dialysis of excitatory receptor antagonists was due to compensation by the contralateral VRC was not supported by findings herein. PMID:27687562

State-dependent and -independent effects of dialyzing excitatory neuromodulator receptor antagonists into the ventral respiratory column.

PubMed

Langer, Thomas M; Neumueller, Suzanne E; Crumley, Emma; Burgraff, Nicholas J; Talwar, Sawan; Hodges, Matthew R; Pan, Lawrence; Forster, Hubert V

2017-02-01

Unilateral dialysis of the broad-spectrum muscarinic receptor antagonist atropine (50 mM) into the ventral respiratory column [(VRC) including the pre-Bötzinger complex region] of awake goats increased pulmonary ventilation (V̇i) and breathing frequency (f), conceivably due to local compensatory increases in serotonin (5-HT) and substance P (SP) measured in effluent mock cerebral spinal fluid (mCSF). In contrast, unilateral dialysis of a triple cocktail of antagonists to muscarinic (atropine; 5 mM), neurokinin-1, and 5-HT receptors does not alter V̇i or f, but increases local SP. Herein, we tested hypotheses that 1 ) local compensatory 5-HT and SP responses to 50 mM atropine dialyzed into the VRC of goats will not differ between anesthetized and awake states; and 2 ) bilateral dialysis of the triple cocktail of antagonists into the VRC of awake goats will not alter V̇i or f, but will increase local excitatory neuromodulators. Through microtubules implanted into the VRC of goats, probes were inserted to dialyze mCSF alone (time control), 50 mM atropine, or the triple cocktail of antagonists. We found 1 ) equivalent increases in local 5-HT and SP with 50 mM atropine dialysis during wakefulness compared with isoflurane anesthesia, but V̇i and f only increased while awake; and 2 ) dialyses of the triple cocktail of antagonists increased V̇i, f, 5-HT, and SP (<0.05) during both day and night studies. We conclude that the mechanisms governing local neuromodulator levels are state independent, and that bilateral excitatory receptor blockade elicits an increase in breathing, presumably due to a local, (over)compensatory neuromodulator response. NEW & NOTEWORTHY The two major findings are as follows: 1) during unilateral dialysis of 50 mM atropine into the ventral respiratory column to block excitatory muscarinic receptor activity, a compensatory increase in other neuromodulators was state independent, but the ventilatory response appears to be state dependent; and 2) the hypothesis that absence of decreased V̇i and f during unilateral dialysis of excitatory receptor antagonists was due to compensation by the contralateral VRC was not supported by findings herein. Copyright © 2017 the American Physiological Society.

The activity of the acidic phosphoproteins from the 80 S rat liver ribosome.

PubMed

MacConnell, W P; Kaplan, N O

1982-05-25

The selective removal of acidic phosphoproteins from the 80 S rat liver ribosome was accomplished by successive alcohol extractions at low salt concentration. The resulting core ribosomes lost over 90% of their translation activity and were unable to support the elongation factor 2 GTPase reaction. Both activities were partially restored when the dialyzed extracts were added back to the core ribosome. The binding of labeled adenosine diphosphoribosyl-elongation factor 2 to ribosomes was also affected by extraction and could be reconstituted, although not to the same extent as the GTPase activity associated with elongation factor 2 in the presence of the ribosome. The alcohol extracts of the 80 S ribosome contained mostly phosphoproteins P1 and P2 which could be dephosphorylated and rephosphorylated in solution by alkaline phosphatase and protein kinase, respectively. Dephosphorylation of the P1/P2 mixture in the extracts caused a decrease in the ability of these proteins to reactivate the polyphenylalanine synthesis activity of the core ribosome. However, treatment of the dephosphorylated proteins with the catalytic subunit of 3':5'-cAMP-dependent protein kinase in the presence of ATP reactivated the proteins when compared to the activity of the native extracts. Rabbit antisera raised against the alcohol-extracted proteins were capable of impairing both the polyphenylalanine synthesis reaction and the elongation factor 2-dependent GTPase reaction in the intact ribosomes.

A modified Plasmodium falciparum growth inhibition assay (GIA) to assess activity of plasma from malaria endemic areas.

PubMed

Mlambo, Godfree; Kumar, Nirbhay

2007-02-01

Plasma samples from patients undergoing treatment in malaria endemic countries often contain anti-malaria drugs, that may overstate effects of specific antibodies in growth inhibition assays (GIA). We describe a modified assay that uses drug resistant P. falciparum parasites (W2) that circumvents the requirement for dialyzing samples that may likely contain drugs such as chloroquine and sulfadoxine/pyrimethamine (SP).

Chemotherapy and Biochemistry of Leishmania

DTIC Science & Technology

1985-12-01

Leishmania- sis is initiated when sandflies inject the extracellular prcmastigate form of the parasite into the skin . The promastigotes are...precipitate from the protamine sulfate step was removed by centri- fugation at 15,000 rpm for 15 min at 40. The supernatant was dialyzed in 2 L of...Fig. 13. Only two protein bands could be detected when stained with commassie blue . RNA polymerase activity could not be detected when gels were

PAROTID FLUID CORTISOL AND CORTISONE.

DTIC Science & Technology

Concentrations of parotid fluid cortisol and cortisone, and of plasma dialyzable cortisol, were measured in normal men before and 2 hours after...of 8.5 to 17.7 micrograms/100 ml. after ACTH treatment, and to 39.4 micrograms/100 ml. after administration of the estrogen. However, parotid fluid...the increase in total plasma cortisol (which was over twice as high after administration of estrogen as of ACTH). Thus parotid fluid corticosteroids

Acute symptoms during and between hemodialysis: the relative role of speed, duration, and biocompatibility of dialysis.

PubMed

Skroeder, N R; Jacobson, S H; Lins, L E; Kjellstrand, C M

1994-12-01

The relationship between hemodialysis (HD) symptoms and dialyzer membrane composition and area, blood-flow, treatment duration, urea removal, ultrafiltration volume, leukocyte activation, and complement generation (C3a) was studied in 20 patients undergoing 234 HD treatments by 12 different modes in random order using Cuprophan, hemophane, or polyamide membranes with small or large membrane areas with high Qb (400 ml/min) and short duration (2 h) or low Qb (200 ml/min) and long duration (4 h). Fewer symptoms occurred during the 2-h HD at high Qb than during the 4-h HD with low Qb (19% vs. 32%, p = 0.0351). No differences were observed between different dialyzer membranes or areas. More intradialytic symptoms occurred when urea elimination was high than it was low (p = 0.0044). Leukocyte activation (leukocyte drop) after 15 min of dialysis and complement generation did not influence symptom incidence. Blood pressure changes were mainly influenced by ultrafiltration volume (p < 0.001). Symptoms between dialyses were determined by urea removal and ultrafiltration. Membrane, area, or Qb were of no importance. Thus, duration of dialysis, urea removal, and demand for ultrafiltration, but not membrane composition, area, or biocompatability, are important for the development of HD-related symptoms.

Improvement of liquid stored boar semen quality by removing low molecular weight proteins and supplementation with α-tocopherol.

PubMed

Zakošek Pipan, M; Mrkun, J; Nemec Svete, A; Zrimšek, P

2017-11-01

Seminal plasma contains low-molecular weight components that can exert a harmful effect on sperm function. We have evaluated the effects of removing low-molecular weight components from seminal plasma and adding α-tocopherol on boar semen quality after 72h of liquid storage. Semen was evaluated on the basis of motility, morphology, acrosome integrity, plasma membrane modifications, mitochondrial activity, DNA fragmentation and lipid peroxidation. Thiobarbituric acid reactive substances (TBARS), 8-isoprostane, and antioxidant status (total antioxidant capacity (TAC) and superoxide dismutase activity (SOD)) were measured in seminal plasma. Removal of low-molecular weight components from seminal plasma, together with the addition of α-tocopherol, kept the lipid peroxidation and mitochondrial activity and DNA fragmentation at the same level as in native semen samples. Dialysing semen and adding 200μM of α-tocopherol led to higher progressive motility, a higher proportion of morphologically normal spermatozoa and a significantly lower level of acrosomal reacted spermatozoa compared to non-dialyzed semen samples after 72h of storage. In conclusion, liquid stored boar semen was better preserved, and oxidative stress in the semen was reduced when semen was dialyzed and α-tocopherol was added prior to storage. Copyright © 2017 Elsevier B.V. All rights reserved.

Removal of methadone by extended dialysis using a high cut-off dialyzer: implications for the treatment of overdose and for pain management in patients undergoing light chain removal.

PubMed

Arelin, Viktor; Schmidt, Julius J; Kayser, Nathalie; Kühn-Velten, W Nikolaus; Suhling, Hendrik; Eden, Gabriele; Kielstein, Jan T

2016-06-01

The synthetic opioid methadone hydrochloride has a low molecular weight of 346 D, a high volume of distribution (4 - 7 L/kg), and is lipophilic. It is used as an analgesic and for the maintenance treatment of opiate dependence. In drug addicts, methadone is frequently involved in mixed intoxications that can lead to death. Here we present the case of a drug addict in whom a high cut-off dialysis membrane together with extended dialysis was used in the setting of suspected overdose and acute kidney injury. Although the observed dialyzer plasma clearance (31.5 mL/min) and reduction ratio (38%) were higher than previously reported for standard hemodialysis, the total amount of methadone in the spent dialysate after 1 extended dialysis session was quite low. Hence, even extended dialysis with a high cut-off membrane does not seem to offer a clinically relevant benefit in the setting of overdose for enhanced methadone removal. On the other hand, in patients undergoing high cut-off dialysis for the removal of light chains, methadone could still be used as an analgesic without an additional dose after high cut-off hemodialysis.

Ethical challenges with hemodialysis patients who lack decision-making capacity: behavioral issues, surrogate decision-makers, and end-of-life situations.

PubMed

Feely, Molly A; Albright, Robert C; Thorsteinsdottir, Björg; Moss, Alvin H; Swetz, Keith M

2014-09-01

Hemodialysis (HD) is routinely offered to patients with end-stage renal disease in the United States who are ineligible for other renal replacement modalities. The frequency of HD among the US population is greater than all other countries, except Taiwan and Japan. In US, patients are often dialyzed irrespective of age, comorbidities, prognosis, or decision-making capacity. Determination of when patients can no longer dialyze is variable and can be dialysis-center specific. Determinants may be related to progressive comorbidities and frailty, mobility or access issues, patient self-determination, or an inability to tolerate the treatment safely for any number of reasons (e.g., hypotension, behavioral issues). Behavioral issues may impact the safety of not only patients themselves, but also those around them. In this article the authors present the case of an elderly patient on HD with progressive cognitive impairment and combative behavior placing him and others at risk of physical harm. The authors discuss the medical, ethical, legal, and psychosocial challenges to care of such patients who lack decision-making capacity with a focus on variable approaches by regions and culture. This manuscript provides recommendations and highlights resources to assist nephrologists, dialysis personnel, ethics consultants, and palliative medicine teams in managing such patients to resolve conflict.

Structural changes in halophilic and non-halophilic proteases in response to chaotropic reagents.

PubMed

Sinha, Rajeshwari; Khare, S K

2014-08-01

Halophilic enzymes have been established for their stability and catalytic abilities under harsh operational conditions. These have been documented to withstand denaturation at high temperature, pH, organic solvents, and chaotropic agents. However, this stability is modulated by salt. The present study targets an important aspect in understanding protein-urea/GdmCl interactions using proteases from halophilic Bacillus sp. EMB9 and non-halophilic subtilisin (Carlsberg) from Bacillus licheniformis as model systems. While, halophilic protease containing 1 % (w/v) NaCl (0.17 M) retained full activity towards urea (8 M), non-halophilic protease lost about 90 % activity under similar conditions. The secondary and tertiary structure were lost in non-halophilic but preserved for halophilic protein. This effect could be due to the possible charge screening and shielding of the protein surface by Ca(2+) and Na(+) ions rendering it stable against denaturation. The dialyzed halophilic protease almost behaved like the non-halophilic counterpart. Incorporation of NaCl (up to 5 %, w/v or 0.85 M) in dialyzed EMB9 protease containing urea/GdmCl, not only helped regain of proteolytic activity but also evaded denaturing action. Deciphering the basis of this salt modulated stability amidst a denaturing milieu will provide guidelines and templates for engineering stable proteins/enzymes for biotechnological applications.

Effect of increasing the colloidal calcium phosphate of milk on the texture and microstructure of yogurt.

PubMed

Ozcan, T; Horne, D; Lucey, J A

2011-11-01

The effect of increasing the colloidal calcium phosphate (CCP) content on the physical, rheological, and microstructural properties of yogurt was investigated. The CCP content of heated (85°C for 30 min) milk was increased by increasing the pH by the addition of alkali (NaOH). Alkalized milk was dialyzed against pasteurized skim milk at approximately 4°C for 72 h to attempt to restore the original pH and soluble Ca content. By adjustment of the milk to pH values 7.45, 8.84, 10.06, and 10.73, the CCP content was increased to approximately 107, 116, 123, and 128%, respectively, relative to the concentration in heated milk. During fermentation of milk, the storage modulus (G') and loss tangent values of yogurts were measured using dynamic oscillatory rheology. Large deformation rheological properties were also measured. The microstructure of yogurt was observed using fluorescence microscopy, and whey separation was determined. Acid-base titration was used to evaluate changes in the CCP content in milk. Total Ca and casein-bound Ca increased with an increase in the pH value of alkalization. During acidification, elevated buffering occurred in milk between pH values 6.7 to 5.2 with an increase in the pH of alkalization. When acidified milk was titrated with alkali, elevated buffering occurred in milk between pH values 5.6 to 6.4 with an increase in the pH of alkalization. The high residual pH of milk after dialysis could be responsible for the decreased contents of soluble Ca in these milks. The pH of gelation was higher in all dialyzed samples compared with the heated control milk, and the gelation pH was higher with an increase in CCP content. The sample with highest CCP content (128%) exhibited gelation at very high pH (6.3), which could be due to alkali-induced CN micellar disruption. The G' values at pH 4.6 were similar in gels with CCP levels up to 116%; at higher CCP levels, the G' values at pH 4.6 greatly decreased. Loss tangent values at pH 5.1 were similar in all samples except in gels with a CCP level of 128%. For dialyzed milk, the whey separation levels were similar in gels made from milk with up to 107% CCP but increased at higher CCP levels. Microstructure of yogurt gels made from milk with 100 to 107% CCP was similar but very large clusters were observed in gels made from milk with higher CCP levels. By dialyzing heated milk against pasteurized milk, we may have retained some heat-induced Ca phosphate on micelles that normally dissolves on cooling because, during dialysis, pasteurized milk provided soluble Ca ions to the heated milk system. Yogurt texture was significantly affected by increasing the casein-bound Ca (and total Ca) content of milk as well as by the alkalization procedure involved in that approach. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Somatopsychic correlates and quality of life of the dialyzed patient: a cross-sectional study.

PubMed

De Pasquale, C; Pistorio, M L; Lauretta, I; Fatuzzo, P; Fornaro, M; Conti, D; Di Nuovo, S; Sinagra, N; Giaquinta, A; Zerbo, D; Veroux, M

2014-09-01

The dialysis delivered after a chronic kidney disease (CDK) or any otherwise severe end-stage renal failure is a complex medical task, leading to major medical and psychopathological distress for the patient. The aim of the present study was to analyze the impact of the dialysis experience on the nephrologic patient's global quality of life. In the present cross-sectional study, involving 96 patients with end-stage renal disease receiving hemodialysis, demographic, medical, and psychological differential features across different CDK diagnoses were accounted and were then correlated each other. Among other differential features, the "acknowledgement of dependence" (from the medical device delivering the dialysis) emerged as a factor correlated to "self-sufficiency" in CDK patients receiving hemodialysis. Although further, larger-sampled studies on the topic are needed, medical and psychological interventions are useful to ensure a better global quality of life and good therapeutic adherence in dialysis patients. Copyright © 2014 Elsevier Inc. All rights reserved.

End-stage renal care in developing countries: the India experience.

PubMed

Jha, Vivekanand

2004-05-01

Chronic renal failure is a devastating medical, social and economic problem for patients and their families. There is no data on the true incidence and prevalence of chronic renal failure in the developing world. Delayed diagnosis and failure of institution of measures to slow progression of renal failure result in a predominantly young ESRD population. Renal replacement therapy (RRT) is a low-priority area for healthcare planners in developing nations with two-tier healthcare delivery system. There is a severe shortage of nephrologists and hospitals offering dialysis and transplantation, more so in the poorest regions. There is a direct relationship between the number of dialysis centers and per capita gross national income of developing nations. Shortage in the number of government-funded hospitals has fanned the growth of a large number of private hospitals offering RRT. The high cost of hemodialysis (HD) puts it beyond the reach of all but the very rich and maintenance HD is the exclusively preserve of private hospitals. Government-run hospitals are busy with renal transplantation, which is the only realistic long term RRT option for a majority of patients. There are no state-funded or private health insurance schemes and patients have to raise finances for RRT on their own. Entire families are involved in such endeavors, with resulting loss of income of other family members too. A number of measures are utilized to bring down the RRT costs. For HD, these include cutting down the frequency of dialysis, use of cheaper cellulosic dialyzers, dialyzer reuse and nonutilization of expensive drugs like erythropoietin. Paradoxically, chronic peritoneal dialysis is more expensive than HD; patients use outdated connection systems and are suboptimally dialyzed on 3 exchanges/day. Most patients on dialysis are inadequately rehabilitated. Renal transplant recipients are forced to discontinue expensive drugs like cyclosporine after variable periods leading to high rates of graft loss. Financial considerations often preclude appropriate treatment of steroid-resistant rejection and cytomegalovirus infection. There is no organized cadaver donation program and an overwhelming majority of transplants are performed using living donors. This led to the practice of the sale of kidneys for transplant. To conclude, the financial burden of RRT in developing nations impacts on the lifestyle and future of entire families, and extracts a cost far higher than the actual amount of money spent on treatment.

Apparatus Circulates Sterilizing Gas

NASA Technical Reports Server (NTRS)

Cross, John H.; Schwarz, Ray P.

1991-01-01

Apparatus circulates sterilizing gas containing ethylene oxide and chlorofluorocarbon through laboratory or medical equipment. Confines sterilizing gas, circulating it only through parts to be treated. Consists of two units. One delivers ethylene oxide/chlorofluorocarbon gas mixture and removes gas after treatment. Other warms, humidifies, and circulates gas through equipment to be treated. Process provides reliable sterilization with negligible residual toxicity from ethylene oxide. Particularly suitable for sterilization of interiors of bioreactors, heart/lung machines, dialyzers, or other equipment including complicated tubing.

Novel Treatments for Botulism: Development of Antagonists for Identified Steps in the Action of Botulinum Neurotoxins

DTIC Science & Technology

1989-11-07

dialyzed against the appropriate medium prior to dilution into the bath. The buccal ganglion in Aplysia contain two large, identified cholinergic neurons...transmitters. Micro-injection of nanomolar final concentrations of BoNT A (Fig. 2A) or B (Fig. 2B) into pre-synaptic cholinergic neurons in the buccal ...already been made to use rat pituitary cells together with patch pipette techniques in this study; this system has facilitated intracellular

A New Polysulfone Membrane Dialyzer, NV, with Low-Fouling and Antithrombotic Properties.

PubMed

Oshihara, Wataru; Ueno, Yoshiyuki; Fujieda, Hiroaki

2017-01-01

The biggest problem in routine hemodialysis therapy is possibly the blood pressure fall experienced by patients during dialysis. In contrast, in medium- and long-term hemodialysis therapy, the main problem might be deterioration of arteriosclerosis because of medial calcification associated with dialysis vintage. Both problems are caused by an autonomic imbalance or structural change in the blood vessels. Inflammation due to extracorporeal blood circulation is another possible cause. This inflammation is considered to cause platelets activated by contact and adherence with the membrane surface to aggregate with white blood cells and attack the endothelium of the blood vessels. Therefore, we tried to develop a new membrane with no adsorption and no platelet activation. Polysulfone (PS) membranes with polyvinylpyrrolidone (PVP) as a hydrophilic agent are widely used in dialysis, but blood components adhere to the membrane surface. We developed a new dialyzer, NV, by localizing a new hydrophilic polymer onto the inner surface of a hollow-fiber membrane composed of PS and PVP. The number of platelets that adhered to the NV membrane surface drastically decreased to 0.9% of that with the conventional PS dialysis membrane. We also confirmed the mechanism by which NV realizes clinical improvements in blood pressure drops and inflammation during dialysis, and verified its clinical appeal. Key Messages: The new membrane NV, which inhibits platelet adhesion and is compatible with blood vessels, is clinically beneficial. © 2017 S. Karger AG, Basel.

In Vitro Dialysis of Cytokine-Rich Plasma With High and Medium Cut-Off Membranes Reduces Its Procalcific Activity.

PubMed

Willy, Kevin; Hulko, Michael; Storr, Markus; Speidel, Rose; Gauss, Julia; Schindler, Ralf; Zickler, Daniel

2017-09-01

Recently developed high-flux (HF) dialysis membranes with extended permeability provide better clearance of middle-sized molecules such as interleukins (ILs). Whether this modulation of inflammation influences the procalcific effects of septic plasma on vascular smooth muscle cells (VSMCs) is not known. To assess the effects of high cut-off (HCO) and medium cut-off (MCO) membranes on microinflammation and in vitro vascular calcification we developed a miniature dialysis model. Plasma samples from lipopolysaccharide-spiked blood were dialyzed with HF, HCO, and MCO membranes in an in vitro miniature dialysis model. Afterwards, IL-6 concentrations were determined in dialysate and plasma. Calcifying VSMCs were incubated with dialyzed plasma samples and vascular calcification was assessed. Osteopontin (OPN) and matrix Gla protein (MGP) were measured in VSMC supernatants. IL-6 plasma concentrations were markedly lower with HCO and MCO dialysis. VSMC calcification was significantly lower after incubation with MCO- and HCO-serum compared to HF plasma. MGP and OPN levels in supernatants were significantly lower in the MCO but not in the HCO group compared to HF. In vitro dialysis of cytokine-enriched plasma samples with MCO and HCO membranes reduces IL-6 levels. The induction of vascular calcification by cytokine-enriched plasma is reduced after HCO and MCO dialysis. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Retention of nutrients in green leafy vegetables on dehydration.

PubMed

Gupta, Sheetal; Gowri, B S; Lakshmi, A Jyothi; Prakash, Jamuna

2013-10-01

The objective of the study was to investigate the influence of dehydration on nutrient composition of Amaranthus gangeticus, Chenopodium album, Centella asiatica, Amaranthus tricolor and Trigonella foenum graecum. The green leafy vegetables (GLV) were steam blanched for 5 min after pretreatment and dried in an oven at 60 °C for 10-12 h. The fresh and dehydrated samples were analyzed for selected proximate constituents, vitamins, minerals, antinutrients and dialyzable minerals. Dehydration seems to have little effect on the proximate, mineral and antinutrient content of the GLV. Among the vitamins, retention of ascorbic acid was 1-14%, thiamine 22-71%, total carotene 49-73% and β-carotene 20-69% respectively, of their initial content. Dialyzable iron and calcium in the fresh vegetables ranged between 0.21-3.5 mg and 15.36-81.33 mg/100 g respectively, which reduced to 0.05-0.53 mg and 6.94-58.15 mg/100 g on dehydration. Dehydration seems to be the simplest convenient technology for preserving these sources of micronutrients, especially when they are abundantly available. Irrespective of the losses of vitamins that take place during dehydration, dehydrated GLV are a concentrated natural source of micronutrients and they can be used in product formulations. Value addition of traditional products with dehydrated GLV can be advocated as a feasible food-based approach to combat micronutrient malnutrition.

Slow nocturnal home hemodialysis (SNHHD)--one year later.

PubMed

Ouwendyk, M; Pierratos, A; Francoeur, R; Wallace, L; Sit, W; Vas, S

1996-01-01

High costs and overcrowding of dialysis centres are leading to a global crisis in health care provision. We are developing slow nocturnal home hemodialysis (SNHHD) in which patients dialyze for eight to 10 hours during sleep five to seven nights per week. Vascular access is by means of the Cook silastic jugular catheter. Special precautions are taken to prevent accidental disconnection and air embolism. Dialysis functions are remotely monitored on computer via a modem by trained staff. Five patients have completed five to seven weeks of training and have been successfully performing SNHHD single-handedly (three out of five patients live alone) for 14, 14, 11, 10 and four months respectively. All have discontinued their phosphate binders and increased dietary phosphate intake. Compared with conventional hemodialysis (CHD) results, average pre-dialysis urea and creatinine levels are remarkably reduced to 9.6 mmol/l and 486 umol/l respectively. The average cumulative weekly Kt/V for CHD is 5.0 as compared to 7.7 while on SNHHD. Four out of five patients report sleeping soundly and experience greatly increased energy and stamina. Their days are entirely free. Repeated in-situ re-use of the dialyzer and blood lines will reduce the patient's work and make SNHHD a very inexpensive modality. SNHHD appears to be a widely applicable treatment with many advantages to both the patient and the health care system.

Dialysis in rats with acute renal failure: evaluation of three different dialyzer membranes.

PubMed

Kränzlin, B; Gretz, N; Kirschfink, M; Mujais, S K

1996-11-01

Exposure to complement-activating cellulosic dialysis membranes has been claimed to adversely affect the course of acute renal failure (ARF). To test this hypothesis, male Sprague-Dawley rats were allocated to 2 groups: in Group 1, ARF was induced by bilateral renal artery clamping whereas in Group 2, animals underwent a sham procedure. In each group, rats were further allocated to undergo hemodialysis with either a Cuprophan, a Hemophan, or a polyacrylonitrile minidialyzer on Days 4 and 8 after surgery, or no dialysis. Renal function was measured by inulin clearance on the days after dialysis. Additionally, total complement activity (CH50) was estimated on Days 1, 2, 4, and 8, and complement factor C3 was detected immunohistochemically. The degree of renal failure and the rate of recovery of renal function were similar in all the ARF groups irrespective of whether they had undergone dialysis or not, or of the type of the dialysis membrane. Furthermore, there were no significant differences in the course of CH50 or in the amount and distribution of complement factor C3 in the kidney tissue between the rats of Groups 1 and 2. Our findings refute the hypothesis that in ischemic ARF exposure to complement-activating cellulosic dialysis membranes impairs the recovery of renal function in rats.

Effect of processing on the disappearance of pesticide residues in fresh-cut lettuce: Bioavailability and dietary risk.

PubMed

Camara, Miguel A; Barba, Alberto; Cermeño, Sandra; Martinez, Gracia; Oliva, Jose

2017-12-02

The aim of this research is to establish the processing factors of six pesticides durong the preparation of fresh-cut lettuce and to assess the risk of ingestion of pesticide residues associated with the consumption of the same. A field study was carried out on the dissipation of three insecticides (imidacloprid, tebufenozide, cypermethrin) and three fungicides (metalaxyl, tebuconazole, azoxystrobin) during treatment conditions simulating those used for commercial fresh-cut lettuce. A simultaneous residue analysis method is validated using QuEChERS extraction with acetonitrile and CG-MS and LC-MS/MS analysis. The residues detected after field application never exceed the established Maximum Residue Limits. The processing factors were generally less than 1 (between 0.34 for tebufenozide and 0.53 for imidacloprid), indicating that the process, as a whole, considerably reduces residue levels in processed lettuce compared to fresh lettuce. It is confirmed that cutting, followed by washing and drying, considerably reduces the residues. A matrix effect in the dialyzation of the pesticides is observed and the in vitro study of bioavailability establishes a low percentage of stomach absorption capacity (<15%). The EDI/ADI ratios found in all cases were well below their ADI values, and the dietary exposure assessed (EDI) in fresh-cut lettuce showed no concerns for consumer health.

A Receptor-Coupled Evanescent Biosensor

DTIC Science & Technology

1990-05-01

fibers ....................................... 18 6. The effects of various concentrations of d-TC (0), carbamyl- choline (&), and a𔃾GT (0) on binding of...affinity gel washed with the homogenization buffer containing 0.1% Triton X-100. The affinity gel was then mixed with 50 mL of 1 M carbamy- choline for 4 h...at 23*C, then filtered, and the filtrate, containing carbamyl- choline and the nAChR protein, was dialyzed against 5 mM Tris pH 7.2 to remove the drug

Identification of Bacillus anthracis by Using Monoclonal Antibody to Cell Wall Galactose-N-Acetylglucosamine Polysaccharide

DTIC Science & Technology

1990-02-01

which appear to be directed to an epitope associated with the galactose-N-acetyl-D- glucosamine polysaccharide. Both demonstrated specificity in their...liquid composed primarily of D-galactose and N-acetyl-D-glu - R medium (28) buffered with 50 mM Tris hydrochloride , pH cosamine (12, 13) (Gal-NAG...Ascites fluid (5 ml) was dialyzed (Cel-Line Associates, Inc., Newfield, N.J.). Suspensions against 20 mM Tris hydrochloride (pH 8.0) for 18 to 20 h, were

[Assessment of nutritional status in patients with chronic kidney disease on maintance hemodialysis].

PubMed

Mikolašević, Ivana; Orlić, Lidija; Vidrih, Suzana; Poje, Berislav; Bubić, Ivan; Vujičić, Božidar; Rački, Sanjin

2014-04-01

It is well established that nutritional status is an important factor affecting the outcome and recovery from disease or injury. Assessment of nutritional status is an integral part of care for patients with chronic kidney disease, especially for those treated with dialysis procedures. According to available literature, 18%-80% of patients on dialysis have some form of nutritional deficiency. Furthermore, in patients treated with dialysis procedures there is a rule called 'reverse epidemiology', according which patients with better nutritional status have better survival rate. Therefore, nutritional assessment should detect malnutrition and rate the overall nutritional status of each patient through clinical data categories: medical history, physical examination, nutrition physical examination, psychosocial history, demographics, physical activity, and current medical/surgical issues. Consequently, the main aim of our study was to analyze the nutritional status of our patients treated with hemodialysis procedures. Another aim was to analyze the applicability of measuring skinfold by caliper as a method of nutritional status assessment. During a six-month period, we analyzed 129 patients (57.4% of men and 42.6% of women), mean age 68.1 ± 12.4 years, treated with hemodialysis procedures (24.8% of patients were treated with online hemodiafiltration and 75.2% with standard, conventional hemodialysis) as the method of choice of renal replacement therapy (RRT) for more than 6 months. All patients were dialyzed three times a week for four hours on biocompatible synthetic membranes. The patients treated with online hemodiafiltration were dialyzed on high-flux helixone membranes, while those treated with standard, conventional hemodialysis were dialyzed on polysulfone membranes and helixone low-flux membranes. The mean time of RRT was 71.2 ± 56.7 months. During the study period, in each patient we followed medical history, and clinical and laboratory parameters of nutritional status at 3 and 6 months. To assess the nutritional status, we used dry weight (DW), body mass index (BMI), skinfold caliper measurement (result is correlated with total body fat, FAT), and common laboratory indicators of nutritional status (serum albumin and cholesterol). RE- SULTS: Analyzing the efficiency of skinfold thickness measurement with caliper, we found that the FAT obtained by caliper showed a statistically significant positive correlation with clinical indicators of nutritional status, and with BMI (r = 0.364, p < 0.0001), DW (r = 0.206, p = 0.005) and volume of muscle circumference (r = 0.399, p < 0.0001). Also, FAT showed statistically significant positive correlation with laboratory indicators of nutritional status, including serum albumin (r = 0.299, p = 0.01) and cholesterol (r = 0.225, p = 0.002). There was no statistically significant correlation between the duration of RRT and FAT (p = NS). In clinical practice, as well as for regular evaluation of nutritional status, it is important that the method we used proved efficient, precise, relatively fast and posing less economic burden. From our experience, the measurement of skinfold with caliper is an applicable, relatively quick and inexpensive method for regular assessment of nutritional status in patients treated with hemodialysis proce- dures. Therefore, all patients treated with RRT should undergo nutritional screening and expert help should be available from dietitians or nutritional support teams in order to identify this problem properly in its early stage and to reduce its high prevalence.

The hemodialysis membranes: a historical perspective, current state and future prospect.

PubMed

Cheung, A K; Leypoldt, J K

1997-05-01

Transport and biocompatibility characteristics are two important considerations when choosing hemodialysis membranes. Dialyzer performance depends on clearances of small solutes, middle molecules, and oncotically active proteins. Although complement and neutrophil activation have become the gold standards for biocompatibility testing of dialysis membranes, alterations of other cellular and noncellular blood elements as a result of blood-membrane interactions are also important. Because of concerns about middle molecule transport and biocompatibility, the original cellophane membrane has been gradually replaced by modified cellulosic membranes and synthetic membranes for clinical use. Recent studies suggest that the choice of dialysis membrane influences the clinical outcome of patients in several areas, including intradialytic acute anaphylactoid reactions, beta 2-microglobulin associated amyloidosis, recovery from acute renal failure, and mortality of chronic hemodialysis patients. However, the relative contributions of middle molecule transport, biocompatibility, and other factors in determining these differences in outcome are unclear. Future development of hemodialysis membranes should focus on improving biocompatibility and enhancing clearances of small solutes and middle molecules, while minimizing the loss of larger plasma proteins.

Effect of reuse of polysulfone membrane on oxidative stress during hemodialysis

PubMed Central

Ramakrishna, P.; Reddy, E. Prabhakar; Suchitra, M. M.; Bitla, A. R.; Rao, P. V. Srinivasa; Sivakumar, V.

2012-01-01

Patients with chronic renal failure, especially those on long-term hemodialysis (HD), have a high incidence of premature cardiovascular disease. Oxidative stress, which occurs when there is an excessive free radical production or low antioxidant level, has recently been implicated as a causative factor in atherogenesis. Hourly changes in malondialdehyde (MDA) and antioxidant enzymes, vitamins, lipid profile and ferric reducing ability of plasma (FRAP) were studied with the first use and immediate subsequent reuse of polysulfone dialysis membrane in 27 patients on regular HD treatment. Data were corrected for hemoconcentration and standardized to measure the rate of change. Increase in MDA and erythrocyte catalase along with decrease in plasma vitamin E and FRAP levels and no change in glutathione peroxidase levels were observed as a result of both fresh and reuse dialysis. These findings indicate a net oxidative stress in both fresh as well as dialyzer reuse sessions. There was no significant change in oxidative stress in both fresh and reuse sessions. The oxidative stress with reuse dialysis was less when compared to first use dialysis, but the difference was not statistically significant. PMID:23087556

Urgent-Start Peritoneal Dialysis: A Chance for a New Beginning

PubMed Central

Arramreddy, Rohini; Zheng, Sijie; Saxena, Anjali B.; Liebman, Scott E.; Wong, Leslie

2014-01-01

Peritoneal dialysis (PD) remains greatly underutilized in the United States despite the widespread preference of home modalities among nephrologists and patients. A hemodialysis-centric model of end-stage renal disease care has perpetuated for decades due to a complex set of factors, including late end-stage renal disease referrals and patients who present to the hospital requiring urgent renal replacement therapy. In such situations, PD rarely is a consideration and patients are dialyzed through a central venous catheter, a practice associated with high infection and mortality rates. Recently, the term urgent-start PD has gained momentum across the nephrology community and has begun to change this status quo. It allows for expedited placement of a PD catheter and initiation of PD therapy within days. Several published case reports, abstracts, and poster presentations at national meetings have documented the initial success of urgent-start PD programs. From a wide experiential base, we discuss the multifaceted issues related to urgent-start PD implementation, methods to overcome barriers to therapy, and the potential impact of this technique to change the existing dialysis paradigm. PMID:24246221

Extracorporeal treatment for thallium poisoning: recommendations from the EXTRIP Workgroup.

PubMed

Ghannoum, Marc; Nolin, Thomas D; Goldfarb, David S; Roberts, Darren M; Mactier, Robert; Mowry, James B; Dargan, Paul I; Maclaren, Robert; Hoegberg, Lotte C; Laliberté, Martin; Calello, Diane; Kielstein, Jan T; Anseeuw, Kurt; Winchester, James F; Burdmann, Emmanuel A; Bunchman, Timothy E; Li, Yi; Juurlink, David N; Lavergne, Valery; Megarbane, Bruno; Gosselin, Sophie; Liu, Kathleen D; Hoffman, Robert S

2012-10-01

The EXtracorporeal TReatments In Poisoning (EXTRIP) workgroup was formed to provide recommendations on the use of extracorporeal treatment (ECTR) in poisoning. To test and validate its methods, the workgroup reviewed data for thallium (Tl). After an extensive search, the co-chairs reviewed the articles, extracted the data, summarized findings, and proposed structured voting statements following a predetermined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements and RAND/UCLA Appropriateness Method to quantify disagreement. Blinded votes were compiled, returned, and discussed during a conference call. A second vote determined the final recommendations. Forty-five articles met inclusion criteria. Only case reports and case series were identified, yielding a very low quality of evidence for all recommendations. Data on 74 patients, including 11 who died, were abstracted. The workgroup concluded that Tl is slightly dialyzable and made the following recommendations: ECTR is recommended in severe Tl poisoning (1D). ECTR is indicated if Tl exposure is highly suspected on the basis of history or clinical features (2D) or if the serum Tl concentration is >1.0 mg/L (2D). ECTR should be initiated as soon as possible, ideally within 24-48 hours of Tl exposure (1D), and be continued until the serum Tl concentration is <0.1 mg/L for a minimal duration of 72 hours (2D). Despite Tl's low dialyzability and the limited evidence, the workgroup strongly recommended extracorporeal removal in the case of severe Tl poisoning.

Ratio of cyclase activating and cyclase inactive parathormone (CAP/CIP) in dialysis patients: correlations with other markers of bone disease.

PubMed

Grzegorzewska, A E; Młot, M

2004-01-01

We checked correlation of CAP/CIP with osteoprotegrin (OPG), its soluble ligand (OPGL) and routinely measured parameters of bone turnover in patients treated with peritoneal dialysis (PD) and hemodialysis (HD). In 30 patients (22 HD, 8 PD) we determined serum concentrations of intact parathormone (iPTH), CAP, OPG, OPGL, total Ca, inorganic phosphates (Pi), creatinine, urea, total alkaline phosphatase (AP) and blood pH. CIP was calculated by subtraction of CAP from iPTH. Controls (Cs) included 9 healthy persons in whom iPTH, CAP, OPG and OPGL were measured as well as CIP, CAP/CIP and OPGL/OPG were calculated. Differences between HD and PD patients included dialysis duration, OPGL, OPGL/OPG, AP, Pi, Ca and pH. After adjustment to dialysis duration differences in OPGL/OPG, Pi, Ca and pH remained significant. HD patients differed from Cs in terms of iPTH, CAP, CIP, OPGL, OPG and OPGL/OPG. In whole group of patients iPTH, CAP, CIP but not CAP/CIP correlated negatively with OPGL and OPGL/OPG as well as positively with dialysis duration, OPG and AP. Despite more advanced uremic bone disease in longer dialyzed HD patients than in shorter dialyzed PD ones, CAP/CIP is not different neither between these groups nor Cs persons. CAP/CIP does not seem to be more powerful tool in noninvasive diagnosis of bone disease than iPTH or CAP and CIP alone.

Bioaccessibility of calcium, iron and magnesium in residues of citrus and characterization of macronutrients.

PubMed

Silva, Joyce Grazielle Siqueira; Rebellato, Ana Paula; Greiner, Ralf; Pallone, Juliana Azevedo Lima

2017-07-01

The aim of this study was to estimate bioaccessibility of Ca, Fe and Mg in residues of orange, lime, and their mixture, in order to evaluate the effects of cooking in water on mineral bioaccessibility and also to determine the composition of macronutrients and myo-inositol phosphate content. The citrus samples contained on average 9.53g/100 g moisture, 6.09g/100 g protein, 3.23g/100g ash, 3.15g/100g lipids, 34.26g/100g insoluble fiber, 27.88g/100g soluble fiber and 25.64g/100g carbohydrates. The percentage of soluble and dialyzable minerals ranged from 19.36 to 77.33% and from 5.59 to 69.06% for Fe, from 33.34 to 60.84% and 14.71 to -26.13% for Ca, and from 29.95 to 94.20% and 34.42 to 62.51%, for Mg, respectively. It was verified that cooking influenced the minerals bioaccessibility and increased the dialyzable fraction of Fe and Mg, but decreased the fraction of Ca dialysate, except to orange. No myoinositol phosphate esters were detected. The Principal Component Analysis allowed the separation of different types of citrus residues, but did not discriminate the raw and cooked samples. This study pointed the potential of citrus residue to be used for human consumption and contribute to the necessary dietary minerals and macronutrients, with high content of soluble and insoluble fibers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth and nutritional status in children with chronic kidney disease on maintenance dialysis in Poland.

PubMed

Stańczyk, Małgorzata; Miklaszewska, Monika; Zachwieja, Katarzyna; Wierciński, Ryszard; Stankiewicz, Roman; Firszt-Adamczyk, Agnieszka; Zachwieja, Jacek; Borzęcka, Hanna; Zagożdżon, Ilona; Ziółkowska, Helena; Leszczyńska, Beata; Medyńska, Anna; Adamczyk, Piotr; Szczepańska, Maria; Tkaczyk, Marcin

2016-03-01

Despite vast availability of modern methods of treatment of chronic kidney disease and its complications, the short stature still is a major point of concern in adolescents with chronic kidney disease. The aim of the study was to assess changes in growth and nutritional status of Polish children on renal replacement therapy in the decade, 2004-2013. The study was designed as a cross-sectional analysis of anthropometric values and selected indices of growth status amongst children receiving dialysis in Poland between the years 2004 and 2013. Data were acquired during two different multicentre studies on hypertension in dialyzed children in Poland. Basic anthropometric parameters (body weight, body height/length, body mass index - BMI), dialysis adequacy and duration of RRT were assessed. The study showed that anthropometric parameters of children undergoing renal replacement therapy had not significantly changed in the last 10 years of observation. Children on RRT were still of short stature despite availability of modern methods of hormonal therapy and nutrition. Median of height z-score was -2.10 in 2004 and -2.19 in 2013. Expected clinical improvement in these measures was not proven. The cause of chronic kidney disease, method of dialysis, time on dialysis or dialysis adequacy did not influence the anthropometric parameters significantly in dialyzed children in Poland. Copyright © 2015 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Parotid fluid cortisol and cortisone

PubMed Central

Katz, Fred H.; Shannon, Ira L.

1969-01-01

Parotid fluid corticosteroids, substantially comprised of cortisol and cortisone, were previously demonstrated to rise to far greater levels 4 hr after administration of ACTH than they did in the third trimester of pregnancy, although the plasma total corticosteroid concentrations were similar in these two states. It was therefore suggested that only nonproteinbound corticosteroid gains access to parotid fluid. In the present study parotid fluid cortisol and cortisone and plasma dialyzable cortisol concentrations have been measured in normal men before and 2 hr after 40 U ACTH, and, in another group, before and after 10 days of diethystilbestrol (5 mg daily). Total plasma cortisol rose from a mean of 6.3 to 17.9 μg/100 ml after ACTH and from 14.6 to 39.4 mg/100 ml after the estrogen. However parotid fluid cortisol plus cortisone rose from 0.8 to 2.6 μg/100 ml after ACTH and to only 2.2 after estrogen. This rise resembled that of the plasma dialyzable cortisol (control 0.4, ACTH 1.8, estrogen 1.2 μg/100 ml) rather than the increase in total plasma cortisol which was over twice as high after estrogen as after ACTH. Thus parotid fluid corticosteroids seem to be a good measure of nonprotein-bound corticosteroid, the cortisol available to the cell. The total amount of cortisol plus cortisone excreted is approximately constant, independent of parotid fluid flow rate. Cortisone exceeds cortisol in parotid fluid in the basal state, but after ACTH the situation is reversed. PMID:4305375

Iris reconstruction using autologous iris preserved in cold balanced salt solution for 8 hours in iatrogenic total iridodialysis during cataract surgery: a case report.

PubMed

Bang, Seung Pil; Jun, Jong Hwa

2017-04-04

A large iris defect or extensive iridodialysis can be an intractable cause of visual disturbance, photophobia, glare, monocular diplopia, or cosmetic deformity. The implantation of an artificial iris substitute could be an effective option, but this can cause a reduction in endothelial cell density. We succeeded in the anatomical restoration of iris tissue that was totally dialyzed out of the eye, and was preserved in cold balanced salt solution for 8 h. Engrafted iris tissue was maintained within the aqueous humor. A 71-year-old man was referred to our clinic for management of an iatrogenic total iridodialysis. The totally dialyzed iris tissue was immediately preserved in sterile cold balanced salt solution and packed in a sterile biopsy bottle that was surrounded with ice cubes. Under general anesthesia, a pars plana vitrectomy was performed to remove the remaining lens cortex and vitreous fiber anterior to the equator. A sulcus-positioned intraocular lens (IOL) was repositioned and fixed by ab externo scleral sutures. Preserved iris tissue was inserted and ironed using both iris spatula and ocular viscoelastic devices. Five-point ab interno scleral sutures were made 1.0 mm posterior to the limbus. The engrafted iris was successfully maintained for 6 months and did not undergo any atrophic change or depigmentation, which may be caused by primary implantation failure due to a blocked blood supply.

Fetal bovine serum and human constitutive androstane receptor: Evidence for activation of the SV23 splice variant by artemisinin, artemether, and arteether in a serum-free cell culture system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lau, Aik Jiang; Chang, Thomas K.H., E-mail: thomas.chang@ubc.ca

The naturally occurring SV23 splice variant of human constitutive androstane receptor (hCAR-SV23) is activated by di-(2-ethylhexyl)phthalate (DEHP), which is detected as a contaminant in fetal bovine serum (FBS). In our initial experiment, we compared the effect of dialyzed FBS, charcoal-stripped, dextran-treated FBS (CS-FBS), and regular FBS on the basal activity and ligand-activation of hCAR-SV23 in a cell-based reporter gene assay. In transfected HepG2 cells cultured in medium supplemented with 10% FBS, basal hCAR-SV23 activity varied with the type of FBS (regular > dialyzed > CS). DEHP increased hCAR-SV23 activity when 10% CS-FBS, but not regular FBS or dialyzed FBS, wasmore » used. With increasing concentrations (1–10%) of regular FBS or CS-FBS, hCAR-SV23 basal activity increased, whereas in DEHP-treated cells, hCAR-SV23 activity remained similar (regular FBS) or slightly increased (CS-FBS). Subsequent experiments identified a serum-free culture condition to detect DEHP activation of hCAR-SV23. Under this condition, artemisinin, artemether, and arteether increased hCAR-SV23 activity, whereas they decreased it in cells cultured in medium supplemented with 10% regular FBS. By comparison, FBS increased the basal activity of the wild-type isoform of hCAR (hCAR-WT), whereas it did not affect the basal activity of the SV24 splice variant (hCAR-SV24) or ligand activation of hCAR-SV24 and hCAR-WT by 6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime (CITCO). The use of serum-free culture condition was suitable for detecting CITCO activation of hCAR-WT and hCAR-SV24. In conclusion, FBS leads to erroneous classification of pharmacological ligands of hCAR-SV23 in cell-based assays, but investigations on functional ligands of hCAR isoforms can be conducted in serum-free culture condition. - Highlights: • FBS leads to erroneous pharmacological classification of hCAR-SV23 ligands. • Artemisinin, artemether, and arteether activate hCAR-SV23 in the absence of FBS. • Serum-free culture condition can be used for identifying ligands of hCAR isoforms.« less

Cell-to-cell diffusion of glucose in the mammalian heart is disrupted by high glucose. Implications for the diabetic heart.

PubMed

De Mello, Walmor C

2015-06-10

The cell-to-cell diffusion of glucose in heart cell pairs isolated from the left ventricle of adult Wistar Kyoto rats was investigated. For this, fluorescent glucose was dialyzed into one cell of the pair using the whole cell clamp technique, and its diffusion from cell-to-cell was investigated by measuring the fluorescence in the dialyzed as well as in non-dialyzed cell as a function of time. The results indicated that: 1) glucose flows easily from cell-to-cell through gap junctions; 2) high glucose solution (25 mM) disrupted chemical communication between cardiac cells and abolished the intercellular diffusion of glucose; 3) the effect of high glucose solution on the cell-to-cell diffusion of glucose was drastically reduced by Bis-1 (10(-9)M) which is a PKC inhibitor; 4) intracellular dialysis of Ang II (100 nM) or increment of intracellular calcium concentration (10(-8)M) also inhibited the intercellular diffusion of glucose; 5) high glucose enhances oxidative stress in heart cells; 6) calculation of gap junction permeability (Pj) (cm/s) indicated a value of 0.74±0.08×10(-4) cm/s (5 animals) for the controls and 0.4±0.001×10(-5) cm/s; n=35 (5 animals) (P<0.05) for cells incubated with high glucose solution for 24h; 7) measurements of Pj for cell pairs treated with high glucose plus Bis-1 (10(-9)M) revealed no significant change of Pj (P>0.05); 8) increase of intracellular Ca(2+) concentration (10(-8)M) drastically decreased Pj (Pj=0.3±0.003×10(-5) cm/s). Conclusions indicate that: 1) glucose flows from cell-to-cell in the heart through gap junctions; 2) high glucose (25 mM) inhibited the intercellular diffusion of glucose-an effect significantly reduced by PKC inhibition; 3) high intracellular Ca(2+) concentration abolished the cell-to-cell diffusion of glucose; 4) intracellular Ang II (100 nM) inhibited the intercellular diffusion of glucose indicating that intracrine Ang II, in part activated by high glucose, severely impairs the exchange of glucose between cardiac myocytes. These observations support the view that the intracrine renin angiotensin system is a modulator of chemical communication in the heart. The implications of these findings for the diabetic heart were discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

[Prospective observational study of angiotensin converting enzyme inhibitors-induced hyperkalemia in hospitalized patients with chronic renal failure].

PubMed

Ben Mahmoud, Lobna; Ghozzi, Hanene; Kammoun, Khawla; Hakim, Ahmed; Kharrat, Mahmoud; Ben Hmida, Mohamed; Jarraya, Faical; Sahnoun, Zouheir; Zeghal, Khaled; Hachicha, Jamil

2013-04-01

To study the incidence and risk factors of angiotensin converting enzyme inhibitors-induced hyperkalemia in hospitalized patients with hypertension and preexisting chronic renal failure. Two-months prospective observational study was used including all hospitalized patients older than 18 years with a history of hypertension, non-dialyzed chronic renal failure and who had angiotensin converting enzyme prescription at the time of the admission. Hyperkalemia greater than or equal to 5 mmol/L was detected in these patients. The studied variables were demographic, clinical, biological and therapeutic. Eight patients, among 27 included, had a hyperkalemia (2963%). They were 73±15 years old. Factors that predispose to hyperkalemia were present in all patients. Hyperkalemia was associated in six cases with decompensation of renal function. The age was associated with hyperkalaemia in patients treated with angiotensin converting enzyme inhibitors (RC=1.21; IC95 1,11-1,46; P=0,021). Diabetes is a possible risk factor (OR=59 021 et, 95 0.93 to 2410, P=0.053). Compared with patients who did not develop hyperkalemia, the occurrence of hyperkalemia in patients included was associated with a longer duration of hospitalization (OR=130, 95 112 to 160, P=0. 022). The prescription of angiotensin converting enzyme inhibitors in the elderly with chronic renal failure and diabetes requires careful monitoring of serum potassium. Copyright © 2012 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Chemoprevention by Elimination of Cancer-Prone, Mutant p53-Containing Breast Cells

DTIC Science & Technology

2009-09-01

Briefly, 50 AL reaction mixture were used for each reaction, which contained 2 QuantiTect SYBR Green RT-PCR Master Mix, 0.5 AL QuantiTect RT mix, 0.5 Amol ...cysteine-free DMEM, containing 5% dialyzed FCS and 50 Amol /L MG132. Cells were then labeled with 100 ACi/mL of [35S]-methionine (MP Biochemicals) for 5 min...with much high drug doses up to 10 Amol /L to achieve a moderate effect. Interestingly, digoxin or ouabain failed to reduce the endogenous wt p53

Bacterial DNA in water and dialysate: detection and significance for patient outcomes.

PubMed

Handelman, Garry J; Megdal, Peter A; Handelman, Samuel K

2009-01-01

The fluid used for hemodialysis may contain DNA fragments from bacteria, which could be harmful for patient outcomes. DNA fragments from bacteria, containing the nonmethylated CpG motif, can trigger inflammation through the monocyte and lymphocyte Toll-like receptor 9, and these DNA fragments have been observed in dialysate. The fragments may transfer across the dialyzer into the patient's bloodstream during hemodialysis treatment. During hemodiafiltration, the fragments would be introduced directly into the bloodstream. The DNA fragments may arise from biofilm in the pipes of the water system, from growth of bacteria in the water, or as contaminants in the bicarbonate and salt mixture used for preparation of dialysate. Current filtration methods, such as Diasafe filters, are not able to remove these fragments. It would be prudent to seek to reduce or eliminate these contaminants. However, the cost and effort of decreasing bacterial DNA content may ultimately require substantial facility improvements; we therefore need to fund research studies to determine if modifications to reduce bacterial DNA content are clinically warranted. This research will require methods to accurately determine the species of bacteria that contribute the DNA, since this information will allow the source to be established as biofilm, bicarbonate mixtures, or other problems in the dialysis system such as bacterial growth or leakage during water preparation. In this review, the evidence for bacterial DNA fragments will be examined and suggestions for further studies will be described.

Assignment of the molecular origins of CEST signals at 2 ppm in rat brain.

PubMed

Zhang, Xiao-Yong; Xie, Jingping; Wang, Feng; Lin, Eugene C; Xu, Junzhong; Gochberg, Daniel F; Gore, John C; Zu, Zhongliang

2017-09-01

Chemical exchange saturation transfer effects at 2 ppm (CEST@2ppm) in brain have previously been interpreted as originating from creatine. However, protein guanidino amine protons may also contribute to CEST@2ppm. This study aims to investigate the molecular origins and specificity of CEST@2ppm in brain. Two experiments were performed: (i) samples containing egg white albumin and creatine were dialyzed using a semipermeable membrane to demonstrate that proteins and creatine can be separated by this method; and (ii) tissue homogenates of rat brain with and without dialysis to remove creatine were studied to measure the relative contributions of proteins and creatine to CEST@2ppm. The experiments indicate that dialysis can successfully remove creatine from proteins. Measurements on tissue homogenates show that, with the removal of creatine via dialysis, CEST@2ppm decreases to approximately 34% of its value before dialysis, which indicates that proteins and creatine have comparable contribution to the CEST@2ppm in brain. However, considering the contribution from peptides and amino acids to CEST@2ppm, creatine may have much less contribution to CEST@2ppm. The contribution of proteins, peptides, and amino acids to CEST@2ppm cannot be neglected. The CEST@2ppm measurements of creatine in rat brain should be interpreted with caution. Magn Reson Med 78:881-887, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Recurrent white thrombi formation in hemodialysis tubing: a case report.

PubMed

Sathe, Kiran P; Yeo, Wee-Song; Liu, Isaac Desheng; Ekambaram, Sudha; Azar, Mohammed; Yap, Hui-Kim; Ng, Kar-Hui

2015-01-15

While the appearance of red clots in the dialyzer is a common phenomenon in every hemodialysis unit, the occurrence of white thrombi in the tubing is relatively rare. We describe an adolescent male with recurrent white thrombi formation in the hemodialysis tubing. This patient had chronic renal failure from focal segmental glomerulosclerosis, but was no longer nephrotic at the time of the thrombi formation. He had a history of recurrent thrombosis of his vascular access. However, no pro-thrombotic risk factors could be identified. White particulate matter, measuring 1 to 3mm in size, and adherent to the arterial and venous blood tubing lines was found during the rinse back of a hemodialysis session. This was associated with a 60% decrease in his platelet count. Light microscopic examination of the deposits revealed the presence of platelet aggregates. He subsequently developed thrombosis of his arteriovenous graft six hours later. The white thrombi recurred at the next dialysis session, as well as six months later. These episodes occurred regardless of the type of dialysis machine or tubing, and appeared to resolve with an increase in heparin dose. Recurrent white thrombi formation can occur in the hemodialysis tubing of a patient with no identifiable pro-thrombotic factors. The white thrombi may be a harbinger of arteriovenous graft thrombosis and may be prevented by an increase in heparin dose.

Robotic technology evolution and transfer

NASA Technical Reports Server (NTRS)

Marzwell, Neville I.

1992-01-01

A report concerning technology transfer in the area of robotics is presented in vugraph form. The following topics are discussed: definition of technology innovation and tech-transfer; concepts relevant for understanding tech-transfer; models advanced to portray tech-transfer process; factors identified as promoting tech-transfer; factors identified as impeding tech-transfer; what important roles do individuals fulfill in tech-transfer; federal infrastructure for promoting tech-transfer; federal infrastructure for promoting tech-transfer; robotic technology evolution; robotic technology transferred; and recommendations for successful robotics tech-transfer.

Biomolecular and structural analyses of cauliflower-like DNAs by ultraviolet, circular dichroism, and fluorescence spectroscopies in comparison with natural DNA.

PubMed

Gill, Pooria; Ranjbar, Bijan; Saber, Reza; Khajeh, Khosro; Mohammadian, Mehdi

2011-07-01

Cauliflower-like DNAs are stem-loop DNAs that are fabricated periodically in inverted repetitions from deoxyribonucleic acid phosphates (dNTPs) by loop-mediated isothermal amplification (LAMP). Cauliflower-like DNAs have ladder-shape behaviors on gel electrophoresis, and increasing the time of LAMP leads to multiplying the repetitions, stem-loops, and electrophoretic bands. Cauliflower-like DNAs were fabricated via LAMP using two loop primers, two bumper primers, dNTPs, a λ-phage DNA template, and a Bst DNA polymerase in 75- and 90-min periods. These times led to manufacturing two types of cauliflower-like DNAs with different contents of inverted repetitions and stem-loops, which were clearly indicated by two comparable electrophoresis patterns in agarose gel. LAMP-fabricated DNAs and natural dsB-DNA (salmon genomic DNA) were dialyzed in Gomori phosphate buffer (10 mM, pH 7.4) to be isolated from salts, nucleotides, and primers. Dialyzed DNAs were studied using UV spectroscopy, circular dichroism spectropolarimetry, and fluorescence spectrophotometry. Structural analyses indicated reduction of the molecular ellipticity and extinction coefficients in comparison with B-DNA. Also, cauliflower-like DNAs demonstrated less intrinsic and more extrinsic fluorescence in comparison with natural DNA. The overwinding and lengthening of the cauliflower-like configurations of LAMP DNAs led to changes in physical parameters of this type of DNA in comparison with natural DNA. The results obtained introduced new biomolecular characteristics of DNA macromolecules fabricated within a LAMP process and show the effects of more inverted repeats and stem-loops, which are manufactured by lengthening the process.

Enhancement of Toxic Substances Clearance from Blood Equvalent Solution and Human Whole Blood through High Flux Dialyzer by 1 MHz Ultrasound

PubMed Central

Shiran, M.B.; Barzegar Marvasti, M.; Shakeri-Zadeh, A.; Shahidi, M.; Tabkhi, N.; Farkhondeh, F.; Kalantar, E.; Asadinejad, A.

2017-01-01

Background: Hemodialysis is a process of removing waste and excess fluid from blood when kidneys cannot function efficiently. It often involves diverting blood to the filter of the dialysis machin to be cleared of toxic substances. Fouling of pores in dialysis membrane caused by adhesion of plasma protein and other toxins will reduce the efficacy of the filtre. Objective: In This study, the influence of pulsed ultrasound waves on diffusion and the prevention of fouling in the filter membrane were investigated. Material and Methods: Pulsed ultrasound waves with frequency of 1 MHz at an intensity of 1 W/cm2 was applied to the high flux (PES 130) filter. Blood and blood equivalent solutions were passed through the filter in separate experimental setups. The amount of Creatinine, Urea and Inulin cleared from both blood equvalent solution and human whole blood passed through High Flux (PES 130) filter were measured in the presence and absence of ultrasound irradiation. Samples were taken from the outlet of the dialyzer every five minutes and the clearance of each constituent was calculated. Results: Statistical analysis of the blood equvalent solution and whole blood indicated the clearance of Urea and Inulin in the presence of ultrasound increased (p<0.05), while no significant effects were observed for Creatinine. Conclusion: It may be concluded that ultrasound, as a mechanical force, can increase the rate of clearance of some toxins (such as middle and large molecules) in the hemodialysis process. PMID:28580332

Lecithin-linker formulations for self-emulsifying delivery of nutraceuticals.

PubMed

Chu, Jacquelene; Cheng, Yu-Ling; Rao, A Venketeshwer; Nouraei, Mehdi; Zarate-Muñoz, Silvia; Acosta, Edgar J

2014-08-25

Lecithin-linker microemulsions are formulations produced with soybean lecithin in combination with a highly lipophilic (lipophilic linker) and highly hydrophilic (hydrophilic linkers) surfactant-like additives. In this work, lecithin-linker systems were formulated to produce self-emulsifying delivery systems for β-carotene and β-sitosterol. The concentration of the lipophilic linker, sorbitan monooleate, was adjusted to minimize the formation of liquid crystals. The concentration of hydrophilic linkers, decaglyceryl caprylate/caprate and PEG-6-caprylic/capric glycerides, was gradually increased (scanned) until single phase clear microemulsions were obtained. For these scans, the oil (ethyl caprate) to water ratio was set to 1. The single phase, clear microemulsions were diluted with fed-state simulated intestinal fluid (FeSSIF) and produced stable emulsions, with drop sizes close to 200 nm. Using pseudo-ternary phase diagrams to evaluate the process of dilution of microemulsion preconcentrates (mixtures of oil, lecithin and linkers with little or no water) with FeSSIF, it was determined that self-emulsifying systems are obtained when the early stages of the dilution produce single phase microemulsions. If liquid crystals or multiple phase systems are obtained during those early stages, then the emulsification yields unstable emulsions with large drop sizes. An in vitro permeability study conducted using a Flow-Thru Dialyzer revealed that stable emulsions with drop sizes of 150-300 nm produce large and irreversible permeation of β-carotene to sheep intestine. On the other hand, unstable emulsions produced without the linker combination separated in the dialyzer chamber. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of disinfectants in renal dialysis patients.

PubMed Central

Klein, E

1986-01-01

Patients receiving hemodialysis therapy risk exposure to both disinfectants and sterilants. Dialysis equipment is disinfected periodically with strong solutions of hypochlorite or formaldehyde. More recently, reuse of dialyzers has introduced the use of additional sterilants, such as hydrogen peroxide and peracetic acid. The use of these sterilants is recognized by the center staffs and the home patient as a potential risk, and residue tests are carried out for the presence of these sterilants at the ppm level. Gross hemolysis resulting from accidental hypochlorite infusion has led to cardiac arrest, probably as a result of hyperkalemia. Formaldehyde is commonly used in 4% solutions to sterilize the fluid paths of dialysis controllers and to sterilize dialyzers before reuse. It can react with red cell antigenic surfaces leading to the formation of anti-N antibodies. Such reactions probably do not occur with hypochlorite or chloramines. The major exposure risk is the low concentration of disinfectant found in municipal water used to prepare 450 L dialysate weekly. With thrice-weekly treatment schedules, the quality requirements for water used to make this solution must be met rigorously. Standards for water used in the preparation of dialysate have recently been proposed but not all patients are treated with dialysate meeting such standards. The introduction of sterilants via tap water is insidious and has led to more pervasive consequences. Both chlorine and chloramines, at concentrations found in potable water, are strong oxidants that cause extensive protein denaturation and hemolysis. Oxidation of the Fe2+ in hemoglobin to Fe3+ forms methemoglobin, which is incapable of carrying either O2 or CO2.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3816735

Development of an Assay for the Early Detection of Organ Specific Carcinogenesis by the Determination and Turnover of NAD(+) and Polyadenosine Diphosphoribose

DTIC Science & Technology

1980-10-28

tion of m-aminophenyl boronic acid was catalyzed by EDAC ( 1 -ethyl- 3 -( 3 dimethylaminopropyl )-carbodiimide HCI), added as 1.5 molar equiv. (to m-amino...from Tubes 7 through 2: 3 were dialyzed overnight against H,0. freeze-dlried,. digested, lid assayed as described under 1 . P’urified histone fl fraction...The phenol phase 3 AD Riso 4 N I-a.8te tated volume i. The corn- -APR.. 1 168 NICOTINIC ACID: ANALOGS AND COENZYMES 1271 1271 supernatants). The

Halophilic Nuclease from a Moderately Halophilic Micrococcus varians

PubMed Central

Kamekura, Masahiro; Onishi, Hiroshi

1974-01-01

The moderately halophilic bacterium Micrococcus varians, isolated from soy sauce mash, produced extracellular nuclease when cultivated aerobically in media containing 1 to 4 M NaCl or KCl. The enzyme, purified to an electrophoretically homogeneous state, had both ribonuclease and deoxyribonuclease activities. The nuclease had maximal activity in the presence of 2.9 M NaCl or 2.1 M KCl at 40 C. The enzymatic activity was lost by dialysis against low-salt buffer, whereas when the inactivated enzyme was dialyzed against 3.4 M NaCl buffer as much as 77% of the initial activity could be restored. Images PMID:4852218

Factors Affecting Training Transfer: Participants' Motivation to Transfer Training, Literature Review

ERIC Educational Resources Information Center

Alawneh, Muhammad K.

2008-01-01

This article investigates factors that motivate participants in learning and training activities to transfer skills, knowledge and attitude from the learning setting to the workplace. Based on training transfer theories hypothesized by Holton (1996), one of the major theories that affect an organization's learning is motivation to transfer theory.…

Influence of indoor environmental factors on mass transfer parameters and concentrations of semi-volatile organic compounds.

PubMed

Wei, Wenjuan; Mandin, Corinne; Ramalho, Olivier

2018-03-01

Semi-volatile organic compounds (SVOCs) in indoor environments can partition among the gas phase, airborne particles, settled dust, and available surfaces. The mass transfer parameters of SVOCs, such as the mass transfer coefficient and the partition coefficient, are influenced by indoor environmental factors. Subsequently, indoor SVOC concentrations and thus occupant exposure can vary depending on environmental factors. In this review, the influence of six environmental factors, i.e., indoor temperature, humidity, ventilation, airborne particle concentration, source loading factor, and reactive chemistry, on the mass transfer parameters and indoor concentrations of SVOCs was analyzed and tentatively quantified. The results show that all mass transfer parameters vary depending on environmental factors. These variations are mostly characterized by empirical equations, particularly for humidity. Theoretical calculations of these parameters based on mass transfer mechanisms are available only for the emission of SVOCs from source surfaces when airborne particles are not present. All mass transfer parameters depend on the temperature. Humidity influences the partition of SVOCs among different phases and is associated with phthalate hydrolysis. Ventilation has a combined effect with the airborne particle concentration on SVOC emission and their mass transfer among different phases. Indoor chemical reactions can produce or eliminate SVOCs slowly. To better model the dynamic SVOC concentration indoors, the present review suggests studying the combined effect of environmental factors in real indoor environments. Moreover, interactions between indoor environmental factors and human activities and their influence on SVOC mass transfer processes should be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

Repeated measurements of transfer factor in rabbits: an animal model suitable for evaluation of short-term exposure.

PubMed

Dahlqvist, M; Lagerstrand, L; Nilsen, A

1994-01-01

Acute temporary changes in lung function may be of use as a biological exposure indicator. However, studies of humans occupationally exposed to complex airborne irritants are often expensive and time demanding. Therefore, an animal model could be a valuable complement. A rabbit model has been evaluated where transfer factor was measured twice during the same day, and with the rabbit awake and available for exposure, in between. Anaesthesia and intubation in 22 rabbits (2.6 [0.2] kg [Mean (SD)]) were immediately followed by two measurements of transfer factor and alveolar volume. Transfer factor was estimated by the single breath CO-technique used in humans. The samples were analysed for CO and He on a gas chromatograph. After one pair of measurements the rabbit was allowed to wake up and after 5 h the duplicate measurements were repeated. The mean values of transfer factor, alveolar volume and transfer constant were 0.50 (0.09) mmol min-1 kPa-1, 127 (8) ml and 3.9 (0.6) mmol min-1 kPa-1 l-1, respectively. The intraindividual coefficients of variation were 7.3%, 5.3% and 6.7%, respectively. Five hours later when the duplicate measurements were repeated, transfer factor, alveolar volume and transfer constant were unchanged still. The results suggest that relatively small changes in transfer factor may be detected without losing power, and thus that this model could be used as a biological exposure indicator.

Development of a general equation to determine the transfer factor feed-to-meat for radiocesium on the basis of the body mass of domestic animals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nalezinski, S.; Ruehm, W.; Wirth, E.

1996-05-01

Transfer factors from feed to meat (5{sub {integral}}), taken from literature for monogastric animals and ruminants have been correlated to their corresponding animal body mass (m{sub b}). Taking all data into account, a close relationship between both transfer factor and body mass becomes evident, yielding a regression function of (T{sub {integral}} = 8.0 x m{sub b}{sup {minus}0.91}) (r = -0.97). For monogastric animals (including poultry), the corresponding relationships are T{sub {integral}} = 1.9 x m{sub b}{sup {minus}0.72} (r = 0.78). The equations offer the opportunity to estimate the transfer factor for individual animals more precisely taking individual body masses intomore » account. They are of interest for animals, on which no or only poor data concerning radiocesium transfer factors are available. The determination of radiocesium transfer factors are reduced to a simple weighing process. 17 refs., 1 fig., 2 tabs.« less

Effect of different dialyzer membranes on cutaneous microcirculation during hemodialysis.

PubMed

Sato, M; Morita, H; Ema, H; Yamaguchi, S; Amano, I

2006-12-01

Biocompatibility profiles of synthetic membranes may vary. In this prospective crossover study, we examined the effect of various membranes on cutaneous microcirculation during HD. 11 HD patients without cardiovascular complications were enrolled in this study. They were dialyzed using three types of membrane in a randomized order: ethylene-vinyl alcohol copolymer (EVAL), vitamin E-bonded cellulose (VE-C) and polysulfone (PS). The transcutaneous oxygen tension (TcPO2) was examined on the dorsum of foot to assess the cutaneous microcirculation. Serum biochemical parameters were also measured. The TcPO2 as a percentage of the predialysis level decreased from the beginning of HD, and significant differences were observed after 15 min of HD between EVAL and the other 2 membranes (98 +/- 6% (mean +/- SD) for EVAL versus 89 +/- 7% for VE-C (p < 0.01) and 88 +/- 10% for PS (p < 0.01)). Furthermore, there were significant differences at 30 and 60 min between EVAL and PS (30 min: 93 +/- 9% for EVAL versus 85 +/- 7% for PS (p < 0.05); 60 min: 92 +/- 10% for EVAL versus 79 +/- 10% for PS (p < 0.01)). The serum level of thiobarbituric acid reactants (TBARs), a marker of lipid peroxidation, increased significantly at the end of HD relative to that at the beginning of HD when using a PS membrane (from 1.9 +/- 0.5 to 2.1 +/- 0.5 nmol/ml, p < 0.05). Our results indicate that an EVAL membrane is superior to PS and VE-C membranes in terms of its smaller influence on cutaneous microcirculation. The repeated occurrence of microcirculatory disturbance during HD sessions may cause chronic endothelial dysfunction and even cardiovascular complications in HD patients.

Pharmacokinetics of Ampicillin/Sulbactam in Critically Ill Patients with Acute Kidney Injury undergoing Extended Dialysis

PubMed Central

Lorenzen, Johan M.; Broll, Michael; Kaever, Volkhard; Burhenne, Heike; Hafer, Carsten; Clajus, Christian; Knitsch, Wolfgang; Burkhardt, Olaf

2012-01-01

Summary Background and objectives The fixed antibacterial combination of ampicillin and sulbactam is frequently used for various infections. Intact kidneys eliminate approximately 71% of ampicillin and 78% of sulbactam. Patients on thrice-weekly low-flux hemodialysis exhibit an ampicillin t1/2 of 2.3 hours on and 17.4 hours off dialysis. Despite its frequent use in intensive care units, there are no available dosing recommendations for patients with AKI undergoing renal replacement therapy. The aims of this study were to evaluate the pharmacokinetics of ampicillin/sulbactam in critically ill patients with AKI undergoing extended dialysis (ED) and to establish a dosing recommendation for this treatment method. Design, setting, participants, & measurements Twelve critically ill patients with anuric AKI being treated with ED were enrolled in a prospective, open-label, observational pharmacokinetic study. Pharmacokinetics after a single dose of ampicillin/sulbactam (2 g/1 g) was obtained in 12 patients. Multiple-dose pharmacokinetics after 4 days of twice-daily ampicillin/sulbactam (2 g/1 g) was obtained in three patients. Results The mean dialyzer clearance for ampicillin/sulbactam was 80.1±7.7/83.3±12.1 ml/min. The t1/2 of ampicillin and sulbactam in patients with AKI undergoing ED were 2.8±0.8 hours and 3.5±1.5 hours, respectively. There was no significant accumulation using a twice-daily dosage of 2 g/1 g ampicillin/sulbactam. Conclusions Our data suggest that in patients treated with ED using a high-flux dialyzer (polysulphone, 1.3 m2; blood and dialysate flow, 160 ml/min; treatment time, 480 minutes), a twice-daily dosing schedule of at least 2 g/1 g ampicillin/sulbactam, with one dose given after ED, should be used to avoid underdosing. PMID:22223613

Hemocompatible polyethersulfone/polyurethane composite membrane for high-performance antifouling and antithrombotic dialyzer.

PubMed

Yin, Zehua; Cheng, Chong; Qin, Hui; Nie, Chuanxiong; He, Chao; Zhao, Changsheng

2015-01-01

Researches on blood purification membranes are fuelled by diverse clinical needs, such as hemodialysis, hemodiafiltration, hemofiltration, plasmapheresis, and plasma collection. To approach high-performance dialyzer, the integrated antifouling and antithrombotic properties are highly necessary for the design/modification of advanced artificial membranes. In this study, we propose and demonstrate that the physical blend of triblock polyurethane (PU) and polyethersulfone (PES) may advance the performance of hemodialysis membranes with greatly enhanced blood compatibility. It was found that the triblock PU could be blended with PES at high ratio owing to their excellent miscibility. The surfaces of the PES/PU composite membranes were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle measurement, and surface ζ-potentials. The results indicated that the membrane surfaces were assembled with hydrophilic segregation layer owing to the migration of amphiphilic PU segments during membrane preparation, which might confer the composite membranes with superior hemocompatibility. The cross-section scanning electron microscopy images of the composite membranes exhibited structure transformation from finger-like structure to sponge-like structure, which indicated that the composite membrane had tunable porosity and permeability. The further ultrafiltration experiments indicated that the composite membranes showed increased permeability and excellent antifouling ability. The blood compatibility observation indicated that PES/PU composite membranes owned decreased protein adsorption, suppressed platelet adhesion, and prolonged plasma recalcification time. These results indicated that the PES/PU composite membranes exhibited enhanced antifouling and antithrombotic properties than the pristine PES membrane. The strategy may forward the fabrication of blood compatible composite membranes for clinical blood dialysis by using the various functional miscible polymers. © 2014 Wiley Periodicals, Inc.

Physiologic volume of phosphorus during hemodialysis: predictions from a pseudo one-compartment model.

PubMed

Leypoldt, John K; Akonur, Alp; Agar, Baris U; Culleton, Bruce F

2012-10-01

The kinetics of plasma phosphorus concentrations during hemodialysis (HD) are complex and cannot be described by conventional one- or two-compartment kinetic models. It has recently been shown by others that the physiologic (or apparent distribution) volume for phosphorus (Vr-P) increases with increasing treatment time and shows a large variation among patients treated by thrice weekly and daily HD. Here, we describe the dependence of Vr-P on treatment time and predialysis plasma phosphorus concentration as predicted by a novel pseudo one-compartment model. The kinetics of plasma phosphorus during conventional and six times per week daily HD were simulated as a function of treatment time per session for various dialyzer phosphate clearances and patient-specific phosphorus mobilization clearances (K(M)). Vr-P normalized to extracellular volume from these simulations were reported and compared with previously published empirical findings. Simulated results were relatively independent of dialyzer phosphate clearance and treatment frequency. In contrast, Vr-P was strongly dependent on treatment time per session; the increase in Vr-P with treatment time was larger for higher values of K(M). Vr-P was inversely dependent on predialysis plasma phosphorus concentration. There was significant variation among predicted Vr-P values, depending largely on the value of K(M). We conclude that a pseudo one-compartment model can describe the empirical dependence of the physiologic volume of phosphorus on treatment time and predialysis plasma phosphorus concentration. Further, the variation in physiologic volume of phosphorus among HD patients is largely due to differences in patient-specific phosphorus mobilization clearance. © 2012 The Authors. Hemodialysis International © 2012 International Society for Hemodialysis.

Extracorporeal treatment for barbiturate poisoning: recommendations from the EXTRIP Workgroup.

PubMed

Mactier, Robert; Laliberté, Martin; Mardini, Joelle; Ghannoum, Marc; Lavergne, Valery; Gosselin, Sophie; Hoffman, Robert S; Nolin, Thomas D

2014-09-01

The EXTRIP (Extracorporeal Treatments in Poisoning) Workgroup conducted a systematic review of barbiturate poisoning using a standardized evidence-based process to provide recommendations on the use of extracorporeal treatment (ECTR) in patients with barbiturate poisoning. The authors reviewed all articles, extracted data, summarized key findings, and proposed structured voting statements following a predetermined format. A 2-round modified Delphi method was used to reach a consensus on voting statements, and the RAND/UCLA Appropriateness Method was used to quantify disagreement. 617 articles met the search inclusion criteria. Data for 538 patients were abstracted and evaluated. Only case reports, case series, and nonrandomized observational studies were identified, yielding a low quality of evidence for all recommendations. Using established criteria, the workgroup deemed that long-acting barbiturates are dialyzable and short-acting barbiturates are moderately dialyzable. Four key recommendations were made. (1) The use of ECTR should be restricted to cases of severe long-acting barbiturate poisoning. (2) The indications for ECTR in this setting are the presence of prolonged coma, respiratory depression necessitating mechanical ventilation, shock, persistent toxicity, or increasing or persistently elevated serum barbiturate concentrations despite treatment with multiple-dose activated charcoal. (3) Intermittent hemodialysis is the preferred mode of ECTR, and multiple-dose activated charcoal treatment should be continued during ECTR. (4) Cessation of ECTR is indicated when clinical improvement is apparent. This report provides detailed descriptions of the rationale for all recommendations. In summary, patients with long-acting barbiturate poisoning should be treated with ECTR provided at least one of the specific criteria in the first recommendation is present. Copyright © 2014 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Hollow-fiber ultrafiltration for simultaneous recovery of viruses, bacteria and parasites from reclaimed water.

PubMed

Liu, Pengbo; Hill, Vincent R; Hahn, Donghyun; Johnson, Trisha B; Pan, Yi; Jothikumar, Narayanan; Moe, Christine L

2012-01-01

Hollow-fiber ultrafiltration (UF) is a technique that has been reported to be effective for recovering a diverse array of microbes from water, and may also be potentially useful for microbial monitoring of effluent from water reclamation facilities. However, few data are available to indicate the potential limitations and efficacy of the UF technique for treated wastewater. In this study, recovery efficiencies were determined for various options available for performing the tangential-flow UF technique, including hollow-fiber ultrafilter (i.e., dialyzer) type, ultrafilter pre-treatment (i.e., blocking), and elution. MS2 and ΦX174 bacteriophages, Clostridium perfringens spores, Escherichia coli, and Cryptosporidium parvum oocysts were seeded into 10-L reclaimed water samples to evaluate UF options. Then a single UF protocol was established and studied using seeded and non-seeded 100-L samples from two water reclamation facilities in Georgia, USA. Baxter Exeltra Plus 210 and Fresenius F200NR dialyzers were found to provide significantly higher microbial recovery than Minntech HPH 1400 hemoconcentrators. The selected final UF method incorporated use of a non-blocked ultrafilter for UF followed by elution using a surfactant-based solution. For 10-L samples, this method achieved recovery efficiencies of greater than 50% recovery of seeded viruses, bacteria, and parasites. There was no significant difference in overall microbial recovery efficiency when the method was applied to 10- and 100-L samples. In addition, detection levels for pathogens in seeded 100-L reclaimed water samples were 1000 PFU HAV, 10,000 GI norovirus particles, <500 Salmonella and <200 Cryptosporidium oocysts. These data demonstrate that UF can be an effective technique for recovering diverse microbes in reclaimed water to monitor and improve effluent water quality in wastewater treatment plants. Published by Elsevier B.V.

Management of ethical issues related to care of seriously ill dialysis patients in free-standing facilities.

PubMed

Song, Mi-Kyung; Hanson, Laura C; Gilet, Constance A; Jo, Minjeong; Reed, Teresa J; Hladik, Gerald A

2014-09-01

There are few data on the frequency and current management of clinical ethical issues related to care of seriously ill dialysis patients in free-standing dialysis facilities. To examine the extent of clinical ethical challenges experienced by care providers in free-standing facilities and their perceptions about how those issues are managed. A total of 183 care providers recruited from 15 facilities in North Carolina completed a survey regarding the occurrence and management of ethical issues in the past year. Care plan meetings were observed at four of the facilities for three consecutive months. Also, current policies and procedures at each of the facilities were reviewed. The two most frequently experienced challenges involved dialyzing frail patients with multiple comorbidities and caring for disruptive/difficult patients. The most common ways of managing ethical issues were discussions in care plan meetings (n = 47) or discussions with the clinic manager (n = 47). Although policies were in place to guide management of some of the challenges, respondents were often not aware of those policies. Also, although participants reported that ethical issues related to dialyzing undocumented immigrants were fairly common, no facility had a policy for managing this challenge. Participants suggested that all staff obtain training in clinical ethics and communication skills, facilities develop ethics teams, and there be clear policies to guide management of ethical challenges. The scope of ethical challenges was extensive, how these challenges were managed varied widely, and there were limited resources for assistance. Multifaceted efforts, encompassing endeavors at the individual, facility, organization, and national levels, are needed to support staff in improving the management of ethical challenges in dialysis facilities. Copyright © 2014 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

[Composition and potential contribution of iron, calcium and zinc of bread and pasta made with wheat and amaranth flours].

PubMed

Dyner, Luis; Drago, Silvina R; Piñeiro, Adriana; Sánchez, Hugo; González, Rolando; Villaamil, Edda; Valencia, Mirta E

2007-03-01

Amaranth, a traditional american crop that is nowadays given renewed importance, has good food potential value. The minerals contributed by the grain are quantitatively important. However, as the flour is obtained by total grinding of the grain, this process leads to the presence of anti-nutritional components, such as fitates, and therefore, the evaluation of the actual availability of the minerals of nutritional interest becomes necessary. The process of bread fermentation, plus the addition of fitases and enhancers of mineral availability such as citric and ascorbic acid, might improve mineral bioavailability. The objective of this work was to assess protein, ash, lipids and total dietary fiber content and evaluate the concentration and dialyzability of Fe, Zn and Ca (as mineral bioavailability indicator) in bread and pasta 100% wheat, and bread and pasta obtained by replacing 20% wheat flour (WF) with whole amaranth flour (WAF). Ascorbic acid (AA), citric acid (CA) and fitase were used as mineral bioavailability enhancers. The potential contribution of each mineral (PC) was calculated as each mineral concentration times its dialyzability. In 80:20 bread an increase of total dietary fiber and minerals, compared to 100% wheat products was observed. A maximum FePC in 80:20 bread was obtained with CA and fitase (0.55mg%). In pasta, the maximum effect was observed with CA (0.07 mg%). The CaPC was maximum in 80:20 pasta with CA (16.72 mg%). The greatest ZnPC was found in 80:20 bread with CA and fitase (0.40 mg%). The introduction of the WAF in fermented baked products with addition of CA and fitase allows to obtain nutritional advantages.

Atropine microdialysis within or near the pre-Botzinger Complex increases breathing frequency more during wakefulness than during NREM sleep.

PubMed

Muere, Clarissa; Neumueller, Suzanne; Miller, Justin; Olesiak, Samantha; Hodges, Matthew R; Pan, Lawrence; Forster, Hubert V

2013-03-01

Normal activity of neurons within the medullary ventral respiratory column (VRC) in or near the pre-Bötzinger Complex (preBötC) is dependent on the balance of inhibitory and excitatory neuromodulators acting at their respective receptors. The role of cholinergic neuromodulation during awake and sleep states is unknown. Accordingly, our objective herein was to test the hypotheses that attenuation of cholinergic modulation of VRC/preBötC neurons in vivo with atropine would: 1) decrease breathing frequency more while awake than during non-rapid-eye-movement (NREM) sleep and 2) increase other excitatory neuromodulators. To test these hypotheses, we unilaterally dialyzed mock cerebrospinal fluid (mCSF) or 50 mM atropine in mCSF in or near the preBötC region of adult goats during the awake (n = 9) and NREM sleep (n = 7) states. Breathing was monitored, and effluent dialysate was collected for analysis of multiple neurochemicals. Compared with dialysis of mCSF alone, atropine increased (P < 0.05) breathing frequency while awake during the day [+10 breaths (br)/min] and at night (+9 br/min) and, to a lesser extent, during NREM sleep (+5 br/min). Atropine increased (P < 0.05) effluent concentrations of serotonin (5-HT), substance P (SP), and glycine during the day and at night. When atropine was dialyzed in one preBötC and mCSF in the contralateral preBötC, 5-HT and SP increased only at the site of atropine dialysis. We conclude: 1) attenuation of a single neuromodulator results in local changes in other neuromodulators that affect ventilatory control, 2) effects of perturbations of cholinergic neuromodulation on breathing are state-dependent, and 3) interpretation of perturbations in vivo requires consideration of direct and indirect effects.

Solute kinetics with short-daily home hemodialysis using slow dialysate flow rate.

PubMed

Kohn, Orly F; Coe, Fredric L; Ing, Todd S

2010-01-01

"NxStage System One()" is increasingly used for daily home hemodialysis. The ultrapure dialysate volumes are typically between 15 L and 30 L per dialysis, substantially smaller than the volumes used in conventional dialysis. In this study, the impact of the use of low dialysate volumes on the removal rates of solutes of different molecular weights and volumes of distribution was evaluated. Serum measurements before and after dialysis and total dialysate collection were performed over 30 times in 5 functionally anephric patients undergoing short-daily home hemodialysis (6 d/wk) over the course of 8 to 16 months. Measured solutes included beta(2) microglobulin (beta(2)M), phosphorus, urea nitrogen, and potassium. The average spent dialysate volume (dialysate plus ultrafiltrate) was 25.4+/-4.7 L and the dialysis duration was 175+/-15 min. beta(2) microglobulin clearance of the polyethersulfone dialyzer averaged 53+/-14 mL/min. Total beta(2)M recovered in the dialysate was 106+/-42 mg per treatment (n=38). Predialysis serum beta(2)M levels remained stable over the observation period. Phosphorus removal averaged 694+/-343 mg per treatment with a mean predialysis serum phosphorus of 5.2+/-1.8 mg/dL (n=34). Standard Kt/V averaged 2.5+/-0.3 per week and correlated with the dialysate-based weekly Kt/V. Weekly beta(2)M, phosphorus, and urea nitrogen removal in patients dialyzing 6 d/wk with these relatively low dialysate volumes compared favorably with values published for thrice weekly conventional and with short-daily hemodialysis performed with machines using much higher dialysate flow rates. Results of the present study were achieved, however, with an average of 17.5 hours of dialysis per week.

Factors influencing training transfer in nursing profession: a qualitative study.

PubMed

Ma, Fang; Bai, Yangjing; Bai, Yangjuan; Ma, Weiguang; Yang, Xiangyu; Li, Jiping

2018-03-20

There is a growing recognition that training is not translated into performance and the 'transfer problem' exists in organization training today. Although factors contributing to training transfer have been identified in business and industry, the factors influencing training transfer in nursing profession remain less clear. A qualitative descriptive study was undertaken in two tertiary referral hospitals in China from February 2013 to September 2013. Purposeful sampling of 24 nursing staffs were interviewed about the factors influencing training transfer. Seven themes evolved from the analysis, categorized in 4 main domains, which described the factors influencing training transfer in nursing profession in trainee characteristics, training design, work environment and profession domain. The trainee characteristics domain included attitude and ability. The training design domain included training content and instruction method. The work environment domain included supports as facilitators and opposition as hindrance. The theme pertaining to the profession domain was professional development. Health care managers need to understand the factors influencing training transfer for maximizing the benefits of training. The right beliefs and values about training, the rigorous employee selection for training, the relevance of training content, training instructions facilitating learning and transfer, supports from peer, supervisors and the organization, organizational culture such as change, sharing, learning and support, and professional development are key to successful training transfer. Furthermore, managers should be aware of the opposition from co-workers and find ways to prevent it.

B16-BL6 melanoma cells release inhibitory factor(s) of active pump activity in isolated lymph vessels.

PubMed

Nakaya, K; Mizuno, R; Ohhashi, T

2001-12-01

We investigated whether supernatant cultured with melanoma cell lines B16-BL6 and K1735 or the Lewis lung carcinoma cell line (LLC) can regulate lymphatic pump activity with bioassay preparations isolated from murine iliac lymph vessels. B16-BL6 and LLC supernatants caused significant dilation of lymph microvessels with cessation of pump activity. B16-BL6 supernatant produced dose-related cessation of lymphatic pump activity. There was no significant tachyphylaxis in the supernatant-mediated inhibitory response of lymphatic pump activity. Pretreatment with 3 x 10(-5) M N(omega)-nitro-L-arginine methyl ester (L-NAME) or 10(-7) M or 10(-6) M glibenclamide and 5 x 10(-4) M 5-hydroxydecanoic acid caused significant reduction of supernatant-mediated inhibitory responses. Simultaneous treatment with 10(-3) M L-arginine and 3 x 10(-5) M L-NAME significantly lessened L-NAME-induced inhibition of the supernatant-mediated response, suggesting that endogenous nitric oxide (NO) plays important roles in supernatant-mediated inhibitory responses. Chemical treatment dialyzed substances of <1,000 molecular weight (MW), producing complete reduction of the supernatant-mediated response. In contrast, pretreatment with heating or digestion with protease had no significant effect on supernatant-mediated response. These findings suggest that B16-BL6 cells may release nonpeptide substance(s) of <1,000 MW, resulting in significant cessation of lymphatic pump activity via production and release of endogenous NO and activation of mitochondrial ATP-sensitive K(+) channels.

Relationship between plasma fibroblast growth factor-23 concentration and bone mineralization in children with renal failure on peritoneal dialysis.

PubMed

Wesseling-Perry, Katherine; Pereira, Renata C; Wang, Hejing; Elashoff, Robert M; Sahney, Shobha; Gales, Barbara; Jüppner, Harald; Salusky, Isidro B

2009-02-01

Fibroblast growth factor (FGF)-23 is produced in bone, and circulating levels are markedly elevated in patients with end-stage kidney disease, but the relationship between plasma levels of FGF-23 and bone histology in dialysis patients with secondary hyperparathyroidism is unknown. The aim of the study was to evaluate the correlation between plasma levels of FGF-23 and bone histology in pediatric patients with end-stage kidney disease who display biochemical evidence of secondary hyperparathyroidism. We performed a cross-sectional analysis of the relationship between plasma FGF-23 levels and bone histomorphometry. The study was conducted in a referral center. Participants consisted of forty-nine pediatric patients who were treated with maintenance peritoneal dialysis and who had serum PTH levels (1st generation Nichols assay) greater than 400 pg/ml. There were no interventions. Plasma FGF-23 levels and bone histomorphometry were measured. No correlation existed between values of PTH and FGF-23. Bone formation rates correlated with PTH (r = 0.44; P < 0.01), but not with FGF-23. Higher FGF-23 concentrations were associated with decreased osteoid thickness (r = -0.49; P < 0.01) and shorter osteoid maturation time (r = -0.48; P < 0.01). High levels of FGF-23 are associated with improved indices of skeletal mineralization in dialyzed pediatric patients with high turnover renal osteodystrophy. Together with other biomarkers, FGF-23 measurements may indicate skeletal mineralization status in this patient population.

Biochemical studies of the differentiation of HL-60 cells into monocytes by either IFN, VIT, D/sub 3/ or TPA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyamoto, S.; Whyzmuzis, C.; Oronsky, B.

The authors have studied the differentiation process of the human promyelocytic cell line, HL-60, by treatment of these cells with either gamma interferon, 1, 25 dihydroxyvitamin D/sub 3/ or a phorbol ester, TPA. The cells were grown in RPMI 1640, 10% FCS with each respective agent, then pulsed labeled with /sup 35/S-Met, harvested, lysed and subfractionated by centrifugation into post-ribosomal and ribosomal salt was fractions (RSW). These fractions were examined by SDS gel electrophoresis. The culture supernatant from the treated cells was dialyzed and passed over a heparin agarose affinity column. The absorbed material was eluted from the column bymore » a step-wise salt gradient and analyzed by SDS gel electrophoresis. They have also observed that in a rabbit reticulocyte lysate assay, the RSW from control cells show inhibition of protein synthesis. The RSW from cells treated with either high concentrations (200-1000 units/ml) of gamma interferon, Vit D/sub 3/ or TPA did not show this inhibition. Some possible explanations for this phenomenon are the loss or inactivation of a component necessary for protein synthesis which is triggered by differentiation, or the differentiation-related modulation of translational inhibitor(s). They have used FPLC to further analyze the RSW, but because the factor(s) are present in such small quantities further analytical and more sensitive procedures need to be pursued.« less

Relation of pulmonary vessel size to transfer factor in subjects with airflow obstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musk, A.W.

In a group of 61 consecutive patients undergoing assessment of airflow obstruction, a significant linear relation was demonstrated between measurements of the diameter of the midzonal pulmonary vessels on the plain chest radiographs and transfer factor (diffusing capacity for carbon monoxide) (r = 0.46, p < 0.001). Since reduction in transfer factor has been shown to relate to structural emphysema, reduction in midzone vessel caliber implies the same. However, in the individual patient neither the transfer factor nor structural emphysema can be reliably predicted from midzone vessel diameters alone.

Interaction of emitted sonar pulses and simulated echoes in a false killer whale: an evoked-potential study.

PubMed

Supin, Alexander Ya; Nachtigall, Paul E; Breese, Marlee

2011-09-01

Auditory evoked potentials (AEP) were recorded during echolocation in a false killer whale Pseudorca crassidens. An electronically synthesized and played-back (simulated) echo was triggered by an emitted biosonar pulse, and its intensity was proportional to that of the emitted click. The delay and transfer factor of the echo relative to the emitted click was controlled by the operator. The echo delay varied from 2 to 16 ms (by two-fold steps), and the transfer factor varied within ranges from -45 to -30 dB at the 2-ms delay to -60 to -45 dB at the 16-ms delay. Echo-related AEPs featured amplitude dependence both on echo delay at a constant transfer factor (the longer the delay, the higher amplitude) and on echo transfer factor at a constant delay (the higher transfer factor, the higher amplitude). Conjunctional variation of the echo transfer factor and delay kept the AEP amplitude constant when the delay to transfer factor trade was from -7.1 to -8.4 dB per delay doubling. The results confirm the hypothesis that partial forward masking of the echoes by the preceding emitted sonar pulses serves as a time-varying automatic gain control in the auditory system of echolocating odontocetes. © 2011 Acoustical Society of America

Transfer factors of polonium from soil to parsley and mint.

PubMed

Al-Masri, M S; Al-Hamwi, A; Eadan, Z; Amin, Y

2010-12-01

Transfer factors of (210)Po from soil to parsley and mint have been determined. Artificial polonium isotope ((208)Po) was used as a tracer to determine transfer factor of Po from soil to plant in pot experiments. Two plant growing systems were used for this study namely, an outdoor system and a sheltered system by a polyethylene tent. (208)Po and (210)Po were determined in soil and different parts of the studied plants (stem and leaf), using alpha spectroscopy. The results have shown that there was a clear uptake of (208)Po by roots to leaves and stems of both plants. Higher values of transfer factors using the (210)Po activity concentrations than the (208)Po activity concentration were observed. Transfer factors of (210)Po from soil to parsley varied between 20 × 10⁻² and 50 × 10⁻² and 22 × 10⁻³ and 67 × 10⁻³ in mint, while (208)Po transfer factors varied between 4 × 10⁻² and 12 × 10⁻² for parsley and 10 × 10⁻² and 22 × 10⁻² in mint. Transfer factors of Po were higher in those plants grown in the sheltered system than in the open system; about 75% of Po was transferred from atmosphere to parsley parts using the two systems. Ratios of transferred Po from soil to mint stem and leaf in the sheltered system were higher by 2 times from those in the open system. Copyright © 2010 Elsevier Ltd. All rights reserved.

Transfer of Patients in a Telestroke Network: What Are the Relevant Factors for Making This Decision?

PubMed

Klingner, Carsten M; Brodoehl, Stefan; Funck, Laura; Klingner, Caroline C; Berrouschot, Jörg; Witte, Otto W; Günther, Albrecht

2018-02-01

Background/Introduction: Current telestroke network consultations are focused on decision-making in the hyperacute stage of stroke management. The two main questions in telestroke consultations are whether thrombolysis should be initiated and whether the patient should be transferred to a hub hospital. Although guidelines exist for initiating intravenous thrombolytic therapy, the question of whether patients should be transferred is far more elusive. In this study, we investigated the factors involved in the decision to transfer stroke patients to a hub hospital. We were particularly interested in identifying factors that promote or impede the transfer of patients. We enrolled 1,615 cases of telestroke consultation of the University Hospital Jena. The two main factors that independently influenced the probability of transferring a patient were the patient's age and the identification of a proximal vessel occlusion. Interestingly, factors such as the severity of symptoms and the time elapsed from symptom onset were not found to have an independent influence on the decision to transfer a patient. The transfer of most patients was justified by the possibility of performing interventional reperfusion therapy. We discuss the effectiveness of the current decision-making process and possible ways to improve decision-making for a more effective selection of patients who would benefit from transfer. The decision-making process to a transfer patient is not standardized and constitutes a trade-off between the intention to treat all possible patients while avoiding the transfer of patients without treatment options.

Decisions to Transfer Nursing Home Residents to Emergency Departments: A Scoping Review of Contributing Factors and Staff Perspectives.

PubMed

Trahan, Lisa M; Spiers, Jude A; Cummings, Greta G

2016-11-01

Nursing home (NH) residents are a frail and vulnerable population often faced with iatrogenic effects of hospital stays when transferred to emergency departments for acute changes in health status. Avoidable or unnecessary transfers of care need to be identified and defined to prevent unintended harm. The aim of this scoping review was to identify characteristics of avoidable or unnecessary transitions of NH residents to emergency departments, and examine factors influencing decision-making by NH staff, residents, and their family members to transfer nursing home residents to emergency departments. The search strategy began with 5 electronic databases, and a hand search of gray literature. Published qualitative and quantitative studies were included that examined the definition of avoidable or unnecessary transfers, and/or reported factors associated with decision-making to transfer NH residents to emergency departments. Methods included quality assessments, data extraction, and synthesis using content analysis. A total of 783 titles and abstracts were retrieved and screened resulting in 19 included studies. Results describing "avoidable" or "unnecessary" transfers were grouped into 3 dimensions of factors: management of early-acute or low-acuity symptoms and chronic disease management in NHs, ambulatory care-sensitive indicators, and use of post hoc assessments. Five categories of factors contributing to decision-making to transfer were identified: nursing factors, physician factors, facility/resource factors, NH resident/family factors, and health system factors. A consensus on the definition of "avoidable" or "unnecessary" transfers was not found. Findings suggest that transfers of NH residents to emergency departments may be avoided with increased care capacity within NHs. The decision-making process involved in the transfer is influenced by many factors, with intentions of both improving clinical outcomes and maintaining quality of life for the NH resident. Acute changes in health status are contextually specific and decisions must consider not only the resident's acute condition, but also resources available in the NH, and resident and family members' preferences for care. A definition of "avoidable" or "unnecessary" transfer must include reliable measurement, yet remain flexible enough to be generalizable to various care facilities to meet the needs of NH residents and manage required care safely within the NH. Robust research aimed at improving the primary care of NH residents is essential to informing health policy reform and education of those providing care in NHs. Copyright © 2016 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Evaluation of solute penetration across the polysulfone membrane with vitamin E coating.

PubMed

Yamashita, Akihiro C; Masaki, Hidenori; Kobayashi, Eisuke; Sukegawa, Takeshi

2015-10-01

Vitamin E (vit E) is coated on polysulfone (PS) dialysis membrane for antioxidative purpose. The membrane, however, has not yet been evaluated from the mass transfer point of view. We investigated this PS membrane with and without vit E coating in vitro ultrafiltration experiments to identify whether or not the coating influences the mass transfer. Dialyzers that included PS membrane with and without vit E coating were investigated. Aqueous test solution of various solutes including vitamin B12 (VB12 , MW1355), chymotrypsin (chymo, MW25000), and albumin (alb, MW66000) was prepared, and normal ultrafiltration experiments were performed at 310 K. Reverse ultrafiltration experiments in which test solution was filtered from outside to inside the hollow fiber were also performed. Sieving coefficients (SC) were computed for evaluation. SC for VB12 was the same regardless of vit E coating; however, chymo was 0.82 ± 0.01 and 0.86 ± 0.01, respectively, for the membrane with and without vit E. Thus, it would be understood that vit E coating reduces the pore size of the membrane, resulting the reduced transport of larger solutes. Like other PS membrane, SC for alb was decreased over time regardless of vit E coating. More importantly, although the steady-state SC for alb was almost identical in two membranes, PS without vit E showed much greater decrease for the first 2 h, while that with vit E showed very little decrease over time, which suggested the reduced fouling effect due to vit E coating. All the SC values found in reverse ultrafiltration were higher than those found in normal ultrafiltration; moreover, the degree of increase with chymo was approximately 5%, whereas that with alb was approximately 430%, which may be explained by a new model in which wedge effect is taken into consideration for the membrane transport. Vit E coating not only has antioxidative effect but also reduces the fouling that is usually caused by various proteins. © 2015 International Society for Hemodialysis.

Hemoadsorption removes tumor necrosis factor, interleukin-6, and interleukin-10, reduces nuclear factor-kappaB DNA binding, and improves short-term survival in lethal endotoxemia.

PubMed

Kellum, John A; Song, Mingchen; Venkataraman, Ramesh

2004-03-01

Previous studies have shown that inflammatory mediators can be removed from the circulation with hemofiltration and that adsorption plays an important role. Because adsorptive capacity of hollow-fiber dialyzers is limited, we sought to determine whether hemoadsorption using high surface area beads would result in greater mediator removal and improved survival in experimental sepsis. Randomized controlled laboratory experiment. University laboratory. Sixty-six adult Sprague-Dawley rats. We conducted two ex vivo and two in vivo experiments. For in vivo experiments, we administered Escherichia coli endotoxin (20 mg/kg) by intravenous infusion and then randomized each animal to receive either hemoadsorption or a sham circuit for 4 hrs. Hemoadsorption was performed for 4 hrs using an arterial-venous circuit and a CytoSorb cartridge containing 10 g of polystyrene divinyl benzene copolymer beads with a biocompatible polyvinylpyrrolidone coating. Survival time was measured to a maximum of 12 hrs. In a separate set of experiments, we studied 12 animals using the same protocol except that we killed all animals at 4 hrs and removed standardized sections of liver for analysis of nuclear factor-kappaB DNA binding. Mean survival time among hemoadsorption-treated animals was 629+/-114 vs. 518+/-120 mins for sham-treated animals (p <.01). Overall survival (defined at 12 hrs) was also significantly better in the hemoadsorption group, seven of 20 vs. one of 20 (p <.05). Plasma interleukin-6 and interleukin-10 concentrations and liver nuclear factor-kappaB DNA binding were significantly reduced by hemoadsorption. Ex vivo experiments showed no endotoxin adsorption but strengthened our in vivo observations by showing rapid adsorption of tumor necrosis factor, interleukin-6, and interleukin-10. Hemoadsorption was associated with reduced inflammation and improved survival in this murine model of septic shock.

Errors in fluid balance with pump control of continuous hemodialysis.

PubMed

Roberts, M; Winney, R J

1992-02-01

The use of pumps both proximal and distal to the dialyzer during continuous hemodialysis provides control of dialysate and ultrafiltration flow rates, thereby reducing nursing time. However, we had noted unexpected severe extracellular fluid depletion suggesting that errors in pump delivery may be responsible. We measured in vitro the operation of various pumps under conditions similar to continuous hemodialysis. Fluid delivery of peristaltic and roller pumps varied with how the tubing set was inserted in the pump. Piston and peristaltic pumps with dedicated pump segments were more accurate. Pumps should be calibrated and tested under conditions simulating continuous hemodialysis prior to in vivo use.

Bioavailability of ambroxol sustained release preparations. Part II: Single and multiple oral dose studies in man.

PubMed

Janssen, T J; Guelen, P J; Vree, T B; Botterblom, M H; Valducci, R

1988-01-01

The bioavailability of a new ambroxol sustained release preparation (75 mg) based on a dialyzing membrane for controlled release was studied in healthy volunteers after single and multiple oral dose in comparison with a standard sustained release formulation in a cross-over study under carefully controlled conditions. Plasma concentrations of ambroxol were measured by means of a HPLC method. Based on AUC data both preparations are found to be bioequivalent, but show different plasma concentration profiles. The test preparation showed a more pronounced sustained release profile than the reference preparation (single dose) resulting in significantly higher steady state plasma levels.

On the Internal Structure of Bacteriophage Lambda

PubMed Central

Kaiser, A. D.

1966-01-01

The structure of bacteriophage lambda has been studied by electron microscopy of negatively stained particles. The phage particles will eject their DNA if they are heated or dialyzed against a chelating agent. The ghost particles, so formed, have a channel running down their tails. Since the channel is not visible in normal particles, the channel may be filled with part of the DNA molecule. Up to 30% of the ghosts contain round objects about half the internal diameter of the head. The round objects, called "cores," have the same buoyant density as the coat protein. The core may be a protein spool about which the phage DNA is wound. PMID:5967429

Factors affecting the development of somatic cell nuclear transfer embryos in Cattle.

PubMed

Akagi, Satoshi; Matsukawa, Kazutsugu; Takahashi, Seiya

2014-01-01

Nuclear transfer is a complex multistep procedure that includes oocyte maturation, cell cycle synchronization of donor cells, enucleation, cell fusion, oocyte activation and embryo culture. Therefore, many factors are believed to contribute to the success of embryo development following nuclear transfer. Numerous attempts to improve cloning efficiency have been conducted since the birth of the first sheep by somatic cell nuclear transfer. However, the efficiency of somatic cell cloning has remained low, and applications have been limited. In this review, we discuss some of the factors that affect the developmental ability of somatic cell nuclear transfer embryos in cattle.

Examining Mental Health Differences between Transfer and Nontransfer University Students Seeking Counseling Services

ERIC Educational Resources Information Center

Mehr, Kristin E.; Daltry, Rachel

2016-01-01

This article sought to examine the differences between transfer and nontransfer students on mental health factors, social involvement, and academic success. It was found that transfer students had significantly higher scores on several mental health factors as compared to nontransfer students. It was also found that transfer students were less…

Factors in the Transfer of Governance-Facilitation Skills within Farmers' Marketing Organizations in Uganda

ERIC Educational Resources Information Center

Miiro, Richard F.; Mazur, Robert E.; Matsiko, Frank B.

2012-01-01

Purpose: Training transfer has been examined for formal industrial and service organizations in developed countries but rarely for rural organizations in sub-Saharan Africa. This study sought to identify transfer system factors that best explain the transfer of governance-facilitation skills provided to leaders of farmers' marketing organizations…

Factors predisposing nursing home resident to inappropriate transfer to emergency department. The FINE study protocol.

PubMed

Perrin, Amélie; Tavassoli, Neda; Mathieu, Céline; Hermabessière, Sophie; Houles, Mathieu; McCambridge, Cécile; Magre, Elodie; Fernandez, Sophie; Caquelard, Anne; Charpentier, Sandrine; Lauque, Dominique; Azema, Olivier; Bismuth, Serge; Chicoulaa, Bruno; Oustric, Stéphane; Costa, Nadège; Molinier, Laurent; Vellas, Bruno; Bérard, Emilie; Rolland, Yves

2017-09-01

Each year, around one out of two nursing home (NH) residents are hospitalized in France, and about half to the emergency department (ED). These transfers are frequently inappropriate. This paper describes the protocol of the FINE study. The first aim of this study is to identify the factors associated with inappropriate transfers to ED. FINE is a case-control observational study. Sixteen hospitals participate. Inclusion period lasts 7 days per season in each center for a total period of inclusion of one year. All the NH residents admitted in ED during these periods are included. Data are collected in 4 times: before transfer in the NH, at the ED, in hospital wards in case of patient's hospitalization and at the patient's return to NH. The appropriateness of ED transfers (i.e. case versus control NH residents) is determined by a multidisciplinary team of experts. Our primary objective is to determine the factors predisposing NH residents to inappropriate transfer to ED. Our secondary objectives are to assess the cost of the transfers to ED; study the evolution of NH residents' functional status and the psychotropic and inappropriate drugs prescription between before and after the transfer; calculate the prevalence of potentially avoidable transfers to ED; and identify the factors predisposing NH residents to potentially avoidable transfer to ED. A better understanding of the determinant factors of inappropriate transfers to ED of NH residents may lead to proposals of recommendations of better practice in NH and would allow implementing quality improvement programs in the health organization.

The psycholegal factors for juvenile transfer and reverse transfer evaluations.

PubMed

King, Christopher M

2018-01-01

It remains unclear whether forensic mental health assessments for juvenile reverse transfer (to juvenile court) are distinct from those for juvenile transfer (to adult court). This survey consisted of an updated review of transfer and reverse transfer laws (in jurisdictions that have both mechanisms) in light of the generally accepted three-factor model of functional legal capacities involved in transfer evaluations (i.e., risk, sophistication-maturity, and treatment amenability). Results indicated that a majority of states' reverse transfer statutes refer explicitly or implicitly to the same three psycholegal constructs identified as central for transfer. Given the legal similarity between transfer and reverse transfer, potential practice implications and directions for future research are discussed. Copyright © 2017 John Wiley & Sons, Ltd.

Evaluating knowledge transfer practices among construction organization in Malaysia

NASA Astrophysics Data System (ADS)

Zaidi, Mohd Azian; Baharuddin, Mohd Nurfaisal; Bahardin, Nur Fadhilah; Yasin, Mohd Fadzil Mat; Nawi, Mohd Nasrun Mohd; Deraman, Rafikullah

2016-08-01

The aims of this paper is to identify a key dimension of knowledge transfer component to improve construction organization performance. It investigates the effectiveness of present knowledge transfer practices currently adopted by the Malaysian construction organizations and examines the relationship between knowledge transfer factors and organizational factors. A survey among 151 respondents including a different contractor registration grade was employed for the study. The survey shows that a seven-teen (17) factors known as creating shared awareness for information sharing, communication, personal skills,individual attitude,training, organizational culture, information technology,motivation, monitoring and supervision, service quality,information accessibility, information supply, socialization process,knowledge tools, coaching and monitoring, staff briefing and information sharing were identify as a key dimension for knowledge transfer success. This finding suggest that through improvement of each factor, the recognition of the whole strategic knowledge transfer process can be increase thus helping to strengthen the Malaysian construction organization for competitive advantages.

Factors That Influence Transfer of Learning from the Online Environment

ERIC Educational Resources Information Center

Everett, Donna R.

2010-01-01

In this paper the author discusses transfer of learning factors to enhance the work skills and knowledge of online MBA students in a managerial communications course. Qualitative research survey methods were utilized; nVivo 8 was used to manipulate the data in two areas: factors that enhance transfer of learning and when students began to apply…

Second Chances: Investigating Athletes’ Experiences of Talent Transfer

PubMed Central

2015-01-01

Talent transfer initiatives seek to transfer talented, mature individuals from one sport to another. Unfortunately talent transfer initiatives seem to lack an evidence-based direction and a rigorous exploration of the mechanisms underpinning the approach. The purpose of this exploratory study was to identify the factors which successfully transferring athletes cite as facilitative of talent transfer. In contrast to the anthropometric and performance variables that underpin current talent transfer initiatives, participants identified a range of psycho-behavioral and environmental factors as key to successful transfer. We argue that further research into the mechanisms of talent transfer is needed in order to provide a strong evidence base for the methodologies employed in these initiatives. PMID:26600303

Second Chances: Investigating Athletes' Experiences of Talent Transfer.

PubMed

MacNamara, Áine; Collins, Dave

2015-01-01

Talent transfer initiatives seek to transfer talented, mature individuals from one sport to another. Unfortunately talent transfer initiatives seem to lack an evidence-based direction and a rigorous exploration of the mechanisms underpinning the approach. The purpose of this exploratory study was to identify the factors which successfully transferring athletes cite as facilitative of talent transfer. In contrast to the anthropometric and performance variables that underpin current talent transfer initiatives, participants identified a range of psycho-behavioral and environmental factors as key to successful transfer. We argue that further research into the mechanisms of talent transfer is needed in order to provide a strong evidence base for the methodologies employed in these initiatives.

Factors Affecting the Development of Somatic Cell Nuclear Transfer Embryos in Cattle

PubMed Central

AKAGI, Satoshi; MATSUKAWA, Kazutsugu; TAKAHASHI, Seiya

2014-01-01

Nuclear transfer is a complex multistep procedure that includes oocyte maturation, cell cycle synchronization of donor cells, enucleation, cell fusion, oocyte activation and embryo culture. Therefore, many factors are believed to contribute to the success of embryo development following nuclear transfer. Numerous attempts to improve cloning efficiency have been conducted since the birth of the first sheep by somatic cell nuclear transfer. However, the efficiency of somatic cell cloning has remained low, and applications have been limited. In this review, we discuss some of the factors that affect the developmental ability of somatic cell nuclear transfer embryos in cattle. PMID:25341701

Skin autofluorescence as a marker of cardiovascular risk in children with chronic kidney disease.

PubMed

Makulska, Irena; Szczepańska, Maria; Drożdż, Dorota; Polak-Jonkisz, Dorota; Zwolińska, Danuta

2013-01-01

We examined skin autofluorescence (sAF) in chronic kidney disease children (CKD) in relation to renal function and dialysis modality. Twenty children on hemodialysis (HD), 20 on peritoneal dialysis (PD), 36 treated conservatively, and 26 healthy subjects were enrolled into the study. In all children sAF, pulse-wave velocity indexed to height (PWV/ht), left ventricular mass index (LVMI), blood pressure (BP), serum lipid profile, phosphate (P), calcium (Ca), and homocysteine were measured. sAF was significantly elevated in CKD groups vs. controls and was significantly associated with PWV/ht, LVMI, BP, P, Ca × P product and homocysteine. sAF in HD and PD groups was positively correlated with dialysis vintage, and in the predialysis group negatively correlated with glomerular filtration rate (eGFR). Multiple regression analysis showed significant association of sAF with LVMI and P in the CKD patient group, and with dialysis treatment duration and BP in dialyzed children. In CKD children, tissue accumulation of advanced glycation end-products (AGEs) was observed. This was aggravated as eGFR declined and was related to early cardiovascular changes and some biochemical cardiovascular disease (CVD) risk markers. sAF as a non-invasive method may be a useful tool for identification of a clinical risk factors of cardiovascular disease in CKD children.

The time for surgery of peritonitis associated with peritoneal dialysis.

PubMed

Mihalache, O; Bugă, C; Doran, H; Catrina, E; Bobircă, F; Andreescu, A; Mustățea, P; Pătrașcu, T

2016-01-01

Peritonitis is the main complication of peritoneal dialysis (PD) and also an important factor for raising the cost of the method to the level of hemodialysis. Associated with PD, peritonitis is responsible for the increase of morbidity and mortality of the procedure and, at the same time, the main cause of the technique failure. Severe and prolonged peritonitis or repeated episodes of peritonitis lead to ultrafiltration failure. Peritonitis treatment should aim for a rapid remission of inflammation in order to preserve the peritoneal membrane functional integrity. The treatment of PD peritonitis consists mainly of antibiotic therapy, surgical intervention not being usually required. However, it is of outmost importance to differentiate the so-called "catheter related" peritonitis from secondary peritonitis due to visceral lesions, in which the surgical treatment comes first. The confusion between secondary and "catheter related" peritonitis may lead to serious errors in choosing the correct treatment, endangering the patient's life. The differential diagnosis between a refractory or secondary peritonitis in a peritoneal dialyzed patient may be very difficult. In front of a refractory PD peritonitis, surgical exploration must not be delayed. Also we have to keep in mind that the aim of peritonitis treatment is the saving of the peritoneal membrane and not the catheter.

THE PREPARATION AND PROPERTIES OF HIGHLY PURIFIED ASCORBIC ACID OXIDASE

PubMed Central

Powers, Wendell H.; Lewis, Stanley; Dawson, Charles R.

1944-01-01

1. A method is described for the preparation of a highly purified ascorbic acid oxidase containing 0.24 per cent copper. 2. Using comparable activity measurements, this oxidase is about one and a half times as active on a dry weight basis as the hitherto most highly purified preparation described by Lovett-Janison and Nelson. The latter contained 0.15 per cent copper. 3. The oxidase activity is proportional to the copper content and the proportionality factor is the same as that reported by Lovett-Janison and Nelson. 4. When dialyzed free of salt, the blue concentrated oxidase solutions precipitate a dark green-blue protein which carries the activity. This may be prevented by keeping the concentrated solutions about 0.1 M in Na2HPO4. 5. When highly diluted for activity measurements the oxidase rapidly loses activity (irreversibly) previous to the measurement, unless the dilution is made with a dilute inert protein (gelatin) solution. Therefore activity values obtained using such gelatin-stabilized dilute solutions of the oxidase run considerably higher than values obtained by the Lovett-Janison and Nelson technique. 6. The effect of pH and substrate concentration on the activity of the purified oxidase in the presence and absence of inert protein was studied. PMID:19873382

Exploring the characteristics of high-performing hospitals that influence trauma triage and transfer.

PubMed

Gagliardi, Anna R; Nathens, Avery B

2015-02-01

Many trauma patients might be first cared for at nondesignated centers before transfer to a trauma center. Limited research has investigated determinants of timely triage and transfer to identify those amenable to quality improvement. This study explored factors influencing timely triage and transfer in a regional trauma system. Centers (n = 15) with both long and short transfer times (emergency department length of stay before transfer) in Ontario were identified using a regional trauma registry. Physicians and nurses in these centers were interviewed with a view to determining factors that either impeded or enabled rapid decisions regarding the need for transfer to a trauma center. A grounded theory approach and constant comparative technique were used to collect and analyze data. Nineteen physicians and eight nurses participated. Clinician level (experience, training, personality, fear of judgment, nursing role), institutional level (guidelines, continuing education, trauma infrastructure, human resources) and system-level (bed availability, referral center, air transport, communication with trauma centers) factors influenced timely decision making. Participants offered several recommendations to improve care. These included guidelines for transfer, a "no refusal" policy at trauma centers, improved air transport and referral center services, as well as further regionalization. Additional features of hospitals with shorter transfer times included coaching of new staff, team meetings, leadership engagement, sharing of performance data, and minimum work hours for physicians. Numerous interacting factors that may influence trauma triage and transfer were identified. These findings can be used by policy makers, health care managers, and clinicians in emergency departments or trauma centers to evaluate and improve trauma triage and transfer, or plan new services. The findings can also be used by researchers to examine the relevance of these factors in other settings or to implement and evaluate the impact of interventions informed by recommendations generated here.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nisbet, A.F.; Woodman, R.F.M.

A database of soil-to-plant transfer factors for radiocesium and radiostrontium has been compiled for arable crops from published and unpublished sources. The database is more extensive than previous compilations of data published by the International Union of Radioecologists, containing new information for Scandinavia and Greece in particular. It also contains ancillary data on important soil characteristics. The database is sub-divided into 28 soil-crop combinations, covering four soil types and seven crop groups. Statistical analyses showed that transfer factors for radiocesium could not generally be predicted as a function of climatic region, type of experiment, age of contamination, or silt characteristics.more » However, significant relationships accounting for more than 30% of the variability in transfer factor were identified between transfer factors for radiostrontium and soil pH/organic matter status for a few soil-crop combinations. Best estimate transfer factors for radiocesium and radiostrontium were calculated for 28 soil-crop combinations, based on their geometric means: only the edible parts were considered. To predict the likely value of future individual transfer factors, 95% confidence intervals were also derived. A comparison of best estimate transfer factors derived in this study with recommended values published by the International Union of Radioecologists in 1989 and 1992 was made for comparable soil-crop groupings. While there were no significant differences between the best estimate values derived in this study and the 1992 data, radiological assessments that still use 1989 data may be unnecessarily cautious.« less

Identification and characterization of an oocyte factor required for development of porcine nuclear transfer embryos

PubMed Central

Miyamoto, Kei; Nagai, Kouhei; Kitamura, Naoya; Nishikawa, Tomoaki; Ikegami, Haruka; Binh, Nguyen T.; Tsukamoto, Satoshi; Matsumoto, Mai; Tsukiyama, Tomoyuki; Minami, Naojiro; Yamada, Masayasu; Ariga, Hiroyoshi; Miyake, Masashi; Kawarasaki, Tatsuo; Matsumoto, Kazuya; Imai, Hiroshi

2011-01-01

Nuclear reprogramming of differentiated cells can be induced by oocyte factors. Despite numerous attempts, these factors and mechanisms responsible for successful reprogramming remain elusive. Here, we identify one such factor, necessary for the development of nuclear transfer embryos, using porcine oocyte extracts in which some reprogramming events are recapitulated. After incubating somatic nuclei in oocyte extracts from the metaphase II stage, the oocyte proteins that were specifically and abundantly incorporated into the nuclei were identified by mass spectrometry. Among 25 identified proteins, we especially focused on a multifunctional protein, DJ-1. DJ-1 is present at a high concentration in oocytes from the germinal vesicle stage until embryos at the four-cell stage. Inhibition of DJ-1 function compromises the development of nuclear transfer embryos but not that of fertilized embryos. Microarray analysis of nuclear transfer embryos in which DJ-1 function is inhibited shows perturbed expression of P53 pathway components. In addition, embryonic arrest of nuclear transfer embryos injected with anti–DJ-1 antibody is rescued by P53 inhibition. We conclude that DJ-1 is an oocyte factor that is required for development of nuclear transfer embryos. This study presents a means for identifying natural reprogramming factors in mammalian oocytes and a unique insight into the mechanisms underlying reprogramming by nuclear transfer. PMID:21482765

Development and validation of a questionnaire to evaluate the factors influencing training transfer among nursing professionals.

PubMed

Bai, Yangjing; Li, Jiping; Bai, Yangjuan; Ma, Weiguang; Yang, Xiangyu; Ma, Fang

2018-02-13

Most organizations invest in people for training to improve human capital and maximize profitability. Yet it is reported in industry and nursing as well that training effectiveness is constrained because of inadequate transfer of training and the underlying reasons for the transfer problem remain unknown. And there is lack of tool to measure transfer problem. The purpose of this study was to develop and validate a questionnaire to evaluate the scores of factors influencing training transfer (FITT) among nursing professionals. The questionnaire was developed by item generation through interview with nurses and literature review. The FITT was validated in terms of content validity through expert reviews. Psychometric properties of the final instrument were assessed in a sample of 960 nurses with training experiences. The content validity of the instrument were as follows: the IR was 0.8095. 51 items on the 63-item scale had I-CVIs of 1.0 and the remaining 12 items had I-CVIs of 0.88. The S-CVI/UA was 0.976 and the S-CVI/Ave was 0.977. For the exploratory step, principal axis factoring (PAF) was selected for this study. Parallel analysis was used to decide the number of factors to extract and oblimin rotation method was used. Exploratory factor analysis identified a five-factor solution including 53 items, accounting for 68.23% of the total variance. The confirmatory factor analysis showed some support for this five-factor model. The findings demonstrate high internal consistency (Cronbach's alpha = .965). This study indicates that the FITT is a valid and reliable instrument for assessing the factors influencing training transfer among nursing professionals. The FITT can be used to assess individual perceptions of catalysts and barriers to the transfer of training among nursing professionals, which can help promote training transfer and training effectiveness in the workplace.

Transfer factors of natural radionuclides and (137)Cs from soil to plants used in traditional medicine in central Serbia.

PubMed

Djelic, Gorica; Krstic, Dragana; Stajic, Jelena M; Milenkovic, Biljana; Topuzovic, Marina; Nikezic, Dragoslav; Vucic, Dusica; Zeremski, Tijana; Stankovic, Milan; Kostic, Dragana

2016-07-01

Transfer factors of natural radionuclides and (137)Cs from soil to plants used in traditional medicine were determined. The transfer factors (TF) were calculated as Bq kg(-1) of dry plant per Bq kg(-1) of dry soil. Mass activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in soil and plant samples were measured with high purity germanium detector (HPGe). The concentrations of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were determined, as well as the cation exchange capacity (CEC) and the content of exchangeable cations (Ca, Mg, K, Na). Wide ranges of values were obtained for all the metals, especially for Cr and Ni. The Absalom model was used for determination of the amount of (137)Cs transferred from soil to plant based on soil characteristics such as pH, exchangeable potassium, humus and clay contents. The estimated transfer factors were in the range from 0.011 to 0.307 with an arithmetic mean of 0.071, median of 0.050, geometric mean of 0.053 and geometric standard deviation (GSD) of 2.08. This value agreed well with that calculated from the measurements of 0.069, geometric mean 0.040 and GSD 3.19. Correlations between radionuclides, metals, physicochemical properties and transfer factors were determined by Spearman correlation coefficient. There was a strong positive correlation between (137)Cs transfer factor and the ratio of transfer factor for K and (137)Cs. Principal Component Analysis (PCA) was performed in order to identify some pattern of data. Copyright © 2016. Published by Elsevier Ltd.

The characteristics of referring facilities and transferred hand surgery patients: factors associated with emergency patient transfers.

PubMed

Kuo, Phoebe; Hartzell, Tristan L; Eberlin, Kyle R; Miao, Diana; Zurakowski, David; Winograd, Jonathan M; Day, Charles S

2014-03-19

As emergency departments (EDs) become increasingly overwhelmed and specialist coverage in some EDs decreases, patients may be transferred to tertiary or quaternary facilities for specialized care to decrease patient load at transferring facilities. Our objective was to determine whether facilities that transferred patients for hand surgery had hand surgery coverage and to evaluate any nonmedical factors that might have been associated with transfer. A retrospective review was conducted for 1167 visits of hand and wrist patients seen in the EDs of two urban level-I trauma centers. The hand surgery capacity of referring facilities was determined by phone calls to the EDs. Univariate and multivariable analyses were conducted to identify nonmedical factors that could potentially affect the decision to transfer. A total of 155 (13.3%) of 1167 patients arrived from other facilities for specialized hand care. These patients were significantly more likely to be male (p = 0.02), have noncommercial insurance (p = 0.04), require an interpreter (p = 0.01), and arrive between 6:00 p.m. and midnight (p = 0.03). In a multivariable analysis, sex and insurance status were significantly associated with transfer (p < 0.05). The subset of ninety-five patients who were transferred from other EDs was significantly more likely to be male (p < 0.01) and arrive on weekends (p < 0.01) or between 6:00 p.m. and midnight (p < 0.01). Of these patients, seventy-seven (81%) were transferred from an ED that reported partial or full hand surgery coverage. However, only eight (10.4%) received a hand surgery evaluation prior to transfer. The low percentage of patients receiving hand surgery evaluations prior to transfer suggests that referring hospitals are not using their own hand surgeon resources. Nonmedical factors, including noncommercial insurance and off-hour time of initial arrival, may be associated with the decision to transfer patients. Identifying nonmedical factors associated with patient transfers and referrals can enlighten efforts to improve the quality and appropriate use of transfers for specialty care.

Biomimetic materials for protein storage and transport

DOEpatents

Firestone, Millicent A [Elmhurst, IL; Laible, Philip D [Villa Park, IL

2012-05-01

The invention provides a method for the insertion of protein in storage vehicles and the recovery of the proteins from the vehicles, the method comprising supplying isolated protein; mixing the isolated protein with a fluid so as to form a mixture, the fluid comprising saturated phospholipids, lipopolymers, and a surfactant; cycling the mixture between a first temperature and a second temperature; maintaining the mixture as a solid for an indefinite period of time; diluting the mixture in detergent buffer so as to disrupt the composition of the mixture, and diluting to disrupt the fluid in its low viscosity state for removal of the guest molecules by, for example, dialysis, filtering or chromatography dialyzing/filtering the emulsified solid.

Estimation of the bioavailability of zinc and calcium from human, cow's, goat, and sheep milk by an in vitro method.

PubMed

Shen, L; Robberecht, H; Van Dael, P; Deelstra, H

1995-01-01

The availability of zinc and calcium from human, cow's, goat, and sheep milk is evaluated by an in vitro method that involves a simulated human gastrointestinal digestion followed by measurement of dialyzability of zinc and calcium. Zinc availability of milk showed the highest value for human milk (15.0%) and the lowest for sheep milk (1.0%), in both whole and skim milk. Calcium availability of the different types of milk did not differ significantly and ranged between 18 and 23%. No significant differences in availability between whole and skim milk were found for both elements, except for zinc in cow's milk.

Mucopolysaccharide and Protein—Polysaccharide of a Transplantable Rat Chondrosarcoma

PubMed Central

Choi, Haing Ug; Meyer, Karl; Swarm, Richard

1971-01-01

Two mucopolysaccharides, chondroitin 4-sulfate (97.8%) and hyaluronic acid (1.2%), were isolated after exhaustive proteolysis of a transplantable chondrosarcoma of the rat. The chondroitin 4-sulfate was fractionated into three fractions of varying degrees of sulfation and chain length. Keratan sulfate and chondroitin 6-sulfate were absent. Extraction of the fresh tumor gave two protein—polysaccharides of similar carbohydrate composition, one soluble in 0.5 M NaCl, the other insoluble. The latter was solubilized in 4 M guanidine·HCl. A dialyzable fraction from the 4 M guanidine solution may be responsible for the insolubility. Both protein—polysaccharides were antigenic and cross-reacted with similar fractions of bovine and human cartilage. PMID:4252539

Chemical elements in pearl oysters (Paxyodon ponderosus), phytoplankton and estuarine sediments from eastern Amazon (Northern Brazil): Bioaccumulation factors and trophic transfer factors

NASA Astrophysics Data System (ADS)

Vilhena, Maria P. S. P.; Costa, Marcondes L.; Berrêdo, José F.; Paiva, Rosildo S.; Souza, Crisvaldo C. S.

2016-04-01

The current study was conducted near Barcarena County, which is a mid-sized urban center where aluminum ore processing industries (bauxite) and Vila do Conde cargo terminal are located. It aims to discuss the bioaccumulation factors as well as factors related to the trophic transfer of chemical elements in water, oyster, phytoplankton and bottom sediments from an estuary in the Brazilian Northern coast. The bioaccumulation factor (BAF), trophic transfer factor (TTF) and biota-sediment-water were used to correlate the contents of chemical elements found in organisms. The sediment, surface water, phytoplankton and pearl oysters chemical composition was analyzed by ICP-OES and ICP-MS. Pearl oysters showed K, Ca, Mg, P, Mn, Fe, Zn, Al, Ba and Pb accumulation, which concentration increase is associated with their diet (phytoplankton). Al concentrations are 14 times higher in pearl oysters (Paxyodon ponderosus), assuming that they are associated with wastewater emissions and with industrialization processes in the area. BAF and BSAF values are 1000 times higher than the metal concentrations in water and bioavailable fraction concentrations. The oyster-phytoplankton trophic transfer factor indicates that P, Ba, Ca, Na, Cd and Zn showed the largest transfers (from 5 to 19). These trophic transfers may be sufficient to cause significant ecotoxicological effects on the region biota.

Purification of lipase produced by a new source of Bacillus in submerged fermentation using an aqueous two-phase system.

PubMed

Barbosa, José Murillo P; Souza, Ranyere L; Fricks, Alini T; Zanin, Gisella Maria; Soares, Cleide Mara F; Lima, Alvaro S

2011-12-15

This work discusses the application of an aqueous two-phase system for the purification of lipases produced by Bacillus sp. ITP-001 using polyethylene glycol (PEG) and potassium phosphate. In the first step, the protein content was precipitated with ammonium sulphate (80% saturation). The enzyme remained in the aqueous solution and was dialyzed against ultra-pure water for 18 h and used to prepare an aqueous two-phase system (PEG/potassium phosphate). The use of different molecular weights of PEG to purify the lipase was investigated; the best purification factor (PF) was obtained using PEG 20,000g/mol, however PEG 8000 was used in the next tests due to lower viscosity. The influence of PEG and potassium phosphate concentrations on the enzyme purification was then studied: the highest FP was obtained with 20% of PEG and 18% of potassium phosphate. NaCl was added to increase the hydrophobicity between the phases, and also increased the purification factor. The pH value and temperature affected the enzyme partitioning, with the best purifying conditions achieved at pH 6.0 and 4°C. The molecular mass of the purified enzyme was determined to be approximately 54 kDa by SDS-PAGE. According to the results the best combination for purifying the enzyme is PEG 8000g/mol and potassium phosphate (20/18%) with 6% of NaCl at pH 6.0 and 4°C (201.53 fold). The partitioning process of lipase is governed by the entropy contribution. Copyright © 2011 Elsevier B.V. All rights reserved.

Calcium-phosphate and parathyroid intradialytic profiles: A potential aid for tailoring the dialysate calcium content of patients on different hemodialysis schedules.

PubMed

Ferraresi, Martina; Pia, Anna; Guzzo, Gabriella; Vigotti, Federica Neve; Mongilardi, Elena; Nazha, Marta; Aroasio, Emiliano; Gonella, Cinzia; Avagnina, Paolo; Piccoli, Giorgina Barbara

2015-10-01

Severe hyperparathyroidism is a challenge on hemodialysis. The definition of dialysate calcium (Ca) is a pending issue with renewed importance in cases of individualized dialysis schedules and of portable home dialysis machines with low-flow dialysate. Direct measurement of calcium mass transfer is complex and is imprecisely reflected by differences in start-to-end of dialysis Ca levels. The study was performed in a dialysis unit dedicated to home hemodialysis and to critical patients with wide use of daily and tailored schedules. The Ca-phosphate (P)-parathyroid hormone (PTH) profile includes creatinine, urea, total and ionized Ca, albumin, sodium, potassium, P, PTH levels at start, mid, and end of dialysis. "Severe" secondary hyperparathyroidism was defined as PTH > 300 pg/mL for ≥3 months. Four schedules were tested: conventional dialysis (polysulfone dialyzer 1.8-2.1 m(2) ), with dialysate Ca 1.5 or 1.75 mmol/L, NxStage (Ca 1.5 mmol/L), and NxStage plus intradialytic Ca infusion. Dosages of vitamin D, calcium, phosphate binders, and Ca mimetic agents were adjusted monthly. Eighty Ca-P-PTH profiles were collected in 12 patients. Serum phosphate was efficiently reduced by all techniques. No differences in start-to-end PTH and Ca levels on dialysis were observed in patients with PTH levels < 300 pg/mL. Conversely, Ca levels in "severe" secondary hyperparathyroid patients significantly increased and PTH decreased during dialysis on all schedules except on Nxstage (P < 0.05). Our data support the need for tailored dialysate Ca content, even on "low-flow" daily home dialysis, in "severe" secondary hyperparathyroid patients in order to increase the therapeutic potentials of the new dialysis techniques. © 2015 International Society for Hemodialysis.

Transfer of (40)K, (238)U, (210)Pb, and (210)Po from soil to plant in various locations in south of Syria.

PubMed

Al-Masri, M S; Al-Akel, B; Nashawani, A; Amin, Y; Khalifa, K H; Al-Ain, F

2008-02-01

Transfer factors of (40)K, (238)U, (210)Pb, and (210)Po from soil to some agriculture crops in various locations in south of Syria (Dara'a and Assuwaydaa districts) have been determined. Soil and vegetable crops (green pepper, cucumber, tomato, and eggplant), legumes crops (lentil, chickpea, and broad bean), fruit trees (apple, grape, and olives) and cereals (barley and wheat) were collected and analyzed for (238)U, (210)Pb, and (210)Po. The results have shown that higher transfer factors (calculated as Bqkg(-1) dry wt. plant material per Bqkg(-1) dry wt. soil) for (210)Po, (210)Pb and (238)U were observed in vegetable leaves than fruits and cereals leaves; the highest values of transfer factor (TF) for (238)U were found to be 0.1 for straw of chickpea. Transfer factors for (210)Po varied between 2.8x10(-2) and 2 in fruits of eggplant and grain of barley, respectively. In addition, several parameters affecting transfer factors of the radionuclides were evaluated. The results can be considered as base values for TF of natural radionuclides in the region.

Conducting Studies of Transfer of Learning: A Practical Guide

DTIC Science & Technology

1982-01-01

X) = percent transfer (If learning C where: Kall aicrage of grades assigned to experimental :.ttmdents for p~erformlanlce in the aircraft. an average...effectiveness. Human Factors. 1971 . 13(6). 561-567. Roscoe, S.N. A little more on incremental transfer effectiveness. Human Factors. 1972, 14(4), 363-364

Experimental and numerical investigation on heat transfer augmentation in a circular tube under forced convection with annular differential blockages/inserts

NASA Astrophysics Data System (ADS)

Waghole, D. R.

2018-06-01

Investigation on heat transfer by generating turbulence in the fluid stream inside the circular tube is an innovative area of research for researchers. Hence, many techniques are been investigated and adopted for enhancement of heat transfer rate to reduce the size and the cost of the heat exchanger/circular tube. In the present study the effect of differential solid ring inserts /turbulators on heat transfer, friction factor of heat exchanger/circular tube was evaluated through experimentally and numerically. The experiments were conducted in range of 3000 ≤Re≤ 6500 and annular blockages 0 ≤ɸ≤50 %. The heat transfer rate was higher for differential combination of inserts as compared to tube fitted with uniform inserts. The maximum heat transfer was obtained by the use of differential metal circular ring inserts/blockages. From this study, Nusselt number, friction factor and enhancement factor are found as 2.5-3.5 times, 12% - 50.5% and 155% - 195%, respectively with water. Finally new possible correlations for predicting heat transfer and friction factor in the flow of water through the circular tube with differential blockages/inserts are proposed.

Dogs on the Move: Factors Impacting Animal Shelter and Rescue Organizations’ Decisions to Accept Dogs from Distant Locations

PubMed Central

Simmons, Kaitlyn E.; Hoffman, Christy L.

2016-01-01

Long-distance dog transfer programs are a topic of burgeoning interest in the animal welfare community, but little research has focused on such programs. This exploratory study, which surveyed 193 individuals associated with animal shelter and rescue organizations in the United States, evaluated factors that impacted organizations’ decisions to transfer in dogs over long distances (>100 miles) and assessed what criteria were commonly valued by destination organizations. Specifically, we examined the following aspects of long-distance transfer programs: (1) logistics of long-distance dog transfers; (2) factors impacting dog selection; (3) medical requirements; (4) partnerships formed between source and destination organizations; and (5) perceptions of long-distance dog transfer programs by individuals affiliated with the destination organizations. This study revealed that many logistical considerations factor into transfer decisions and the formation of healthy partnerships between source and destination organizations. Participants indicated their organization’s willingness to receive dogs of various sizes, coat colors and ages, but organizations often had restrictions regarding the breeds they would accept. Study findings indicate some organizations have strict quarantine policies and pre-transfer medical requirements, while others have no such requirements. PMID:26848694

Technology Transfer Issues and a New Technology Transfer Model

ERIC Educational Resources Information Center

Choi, Hee Jun

2009-01-01

The following are major issues that should be considered for efficient and effective technology transfer: conceptions of technology, technological activity and transfer, communication channels, factors affecting transfer, and models of transfer. In particular, a well-developed model of technology transfer could be used as a framework for…

Factors, Practices, and Policies Influencing Students' Upward Transfer to Baccalaureate-Degree Programs and Institutions: A Mixed Methods Analysis

ERIC Educational Resources Information Center

LaSota, Robin Rae

2013-01-01

My dissertation utilizes an explanatory, sequential mixed-methods research design to assess factors influencing community college students' transfer probability to baccalaureate-granting institutions and to present promising practices in colleges and states directed at improving upward transfer, particularly for low-income and first-generation…

Transitioning Transfer Students: Interactive Factors that Influence First-Year Retention

ERIC Educational Resources Information Center

Luo, Mingchu; Williams, James E.; Vieweg, Bruce

2007-01-01

This study examined the diverse patterns of interactive factors that influence transfer students' first-year retention at a midsize four-year university. The population for this study consisted of five cohorts totaling 1,713 full-time, degree-seeking transfer students. Sequential sets of logistic regression analyses on blocks of variables were…

Are patients being transferred to level-I trauma centers for reasons other than medical necessity?

PubMed

Koval, Kenneth J; Tingey, Chad W; Spratt, Kevin F

2006-10-01

In the United States, the Emergency Medical Treatment and Active Labor Act defines broad guidelines regarding interhospital transfer of patients who have sought care in the emergency department. However, patient transfers for nonmedical reasons are still considered a common practice. The purpose of this study was to evaluate the possible risk factors for hospital transfer in a population of patients unlikely to require transfer to a level-I center for medical reasons. A retrospective case-control national database study was performed with use of data from the National Trauma Data Bank (version 4.3). The study group consisted of patients with low Injury Severity Scores (< or =9) who were transferred to a level-I trauma center from another hospital. The controls were patients with low Injury Severity Scores who were treated at any hospital that was lower than a level-I trauma center and were not transferred. Hypothesized risk factors for hospital transfer were the age, gender, race, and insurance status of the patient; the time of day the transfer was received; and the number and type of comorbidities. The total sample included 97,393 patients, 21% of whom were transferred to a level-I trauma center. The odds ratios adjusted for all risk factors indicated that transfer rates were higher for male patients compared with female patients (adjusted odds ratio = 1.46), children compared with seniors (3.54), blacks compared with whites (1.28), evening or night transfers compared with morning or afternoon transfers (2.25), patients with Medicaid compared with those with other types of insurance (2.02), and for those with one or more comorbidities compared with those with no comorbidity (2.79). These results suggest the need for prospective studies to further investigate the relationships between hospital transfer and medical and nonmedical factors.

Model wall and recovery temperature effects on experimental heat transfer data analysis

NASA Technical Reports Server (NTRS)

Throckmorton, D. A.; Stone, D. R.

1974-01-01

Basic analytical procedures are used to illustrate, both qualitatively and quantitatively, the relative impact upon heat transfer data analysis of certain factors which may affect the accuracy of experimental heat transfer data. Inaccurate knowledge of adiabatic wall conditions results in a corresponding inaccuracy in the measured heat transfer coefficient. The magnitude of the resulting error is extreme for data obtained at wall temperatures approaching the adiabatic condition. High model wall temperatures and wall temperature gradients affect the level and distribution of heat transfer to an experimental model. The significance of each of these factors is examined and its impact upon heat transfer data analysis is assessed.

[Changes in hemodialysis adequacy in Lithuania during 1999-2005].

PubMed

Ziginskiene, Edita; Kuzminskis, Vytautas; Sileikiene, Elvyra; Tamosaitis, Algirdas; Sirevicius, Virgilijus

2007-01-01

Despite the improvement of hemodialysis technique, mortality of chronic hemodialysis patients remains quite high. It considerably depends on dialysis adequacy. The aim of the study was to evaluate the adequacy of hemodialysis procedure and its changes in Lithuania during 1999-2005. Between 1999 and 2005 in December, all hemodialysis centers in Lithuania were annually visited, and data on the type of hemodialysis, duration of hemodialysis (hours per week), single-pool Kt/V were collected from all hemodialysis patients. The percentage of patients on bicarbonate hemodialysis sharply increased from 57.9% in 1999 to 100% in 2001 (P<0.001), and the duration of hemodialysis procedure increased (67.3% of hemodialysis patients were dialyzed 12 and more hours per week in 2005 vs. 41.3% in 1999, P<0.001). The percentage of patients who were dialyzed three times per week increased from 51% in 1999 to 77% in 2005 (P<0.001). The mean Kt/V was 0.81+/-0.53 in 1999, but it increased to 1.21+/-0.27 in 2005 (P<0.001). More than half (54%) of all hemodialysis patients in 2005 had Kt/V > or =1.2 vs. more than one-third (36%) in 1999 (P<0.001). The mean Kt/V of patients who were on dialysis three times per week was 1.25+/-0.6; two times per week, 1.30+/-0.8; and one time per week, 1.27+/-0.26 in 2003. In 2005, the results were 1.21+/-0.27, 1.22+/-0.26, and 1.16+/-0.29, respectively (P>0.05). CONCLUSIONS. 1. The improvement of the quality of hemodialysis was observed in Lithuania during 1999-2005: a) from 2001, patients received only bicarbonate hemodialysis; b) weekly duration of hemodialysis increased; c) Kt/V improved. 2. Despite the improvement of hemodialysis quality, it is not optimal yet and is associated with insufficient duration of hemodialysis.

The effects of vitamin E-coated membrane dialyzer compared to simvastatin in patients on chronic hemodialysis.

PubMed

Kirmizis, Dimitrios; Papagianni, Aikaterini; Dogrammatzi, Fani; Belechri, Anna-Maria; Alexopoulos, Efstathios; Efstratiadis, Georgios; Memmos, Dimitrios

2012-01-01

We investigated the effects of the use of vitamin E-coated membrane (VEM) dialyzer in comparison to simvastatin on markers of chronic inflammation, oxidative stress, and endothelial cell apoptosis in ten patients on chronic hemodialysis (HD), aiming at distinguishing the different treatment effects and their time sequence on these pathogenetic routes. Ten HD patients were sequentially submitted to a 6-month treatment with the use of VEM and 10 mg of simvastatin daily, interrupted by a 3-month washout period. At baseline, at 3, and 6 months of each trial, serum C-reactive protein (CRP), apolipoprotein (Apo) A1 and B, lipoprotein-a [Lp(a)], high-sensitivity interleukin-6 (hsIL-6), monocyte chemoattractant protein-1 (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), soluble Fas (sFas), soluble Fas ligand (sFasL), and plasma oxidized low-density lipoproteins (oxLDL) levels were determined. VEM treatment resulted in a significant decrease in CRP, IL-6, sICAM-1 at 3 months, and oxLDL at 6 months, compared to baseline. Simvastatin resulted in a significant decrease in CRP, which correlated with decreases in both total (r = 0.87, p < 0.05) and low-density lipoprotein cholesterol, IL-6, sICAM-1, sVCAM-1, oxLDL, and sFas at 6 months, compared to baseline. Simvastatin effects on sVCAM-1 (mean difference = 652 ng/mL; 95% CI = 294 to 2686; p < 0.05) and sFas (mean difference = 1284 pg/mL; 95% CI = 510 to 1910; p < 0.05) differed significantly from the corresponding VEM effects. The 6-month use of VEM resulted in more direct and immediate anti-inflammatory effects compared with those caused by the 6-month treatment with simvastatin. Simvastatin caused a more intense decrease in the markers of inflammation, which was in part correlated with its lipid-lowering effects.

Development of an Accident Reproduction Simulator System Using a Hemodialysis Extracorporeal Circulation System.

PubMed

Nishite, Yoshiaki; Takesawa, Shingo

2016-01-01

Accidents that occur during dialysis treatment are notified to the medical staff via alarms raised by the dialysis apparatus. Similar to such real accidents, apparatus activation or accidents can be reproduced by simulating a treatment situation. An alarm that corresponds to such accidents can be utilized in the simulation model. The aim of this study was to create an extracorporeal circulation system (hereinafter, the circulation system) for dialysis machines so that it sets off five types of alarms for: 1) decreased arterial pressure, 2) increased arterial pressure, 3) decreased venous pressure, 4) increased venous pressure, and 5) blood leakage, according to the five types of accidents chosen based on their frequency of occurrence and the degree of severity. In order to verify the alarm from the dialysis apparatus connected to the circulation system and the accident corresponding to it, an evaluation of the alarm for its reproducibility of an accident was performed under normal treatment circumstances. The method involved testing whether the dialysis apparatus raised the desired alarm from the moment of control of the circulation system, and measuring the time it took until the desired alarm was activated. This was tested on five main models from four dialyzer manufacturers that are currently used in Japan. The results of the tests demonstrated successful activation of the alarms by the dialysis apparatus, which were appropriate for each of the five types of accidents. The time between the control of the circulatory system to the alarm signal was as follows, 1) venous pressure lower limit alarm: 7 seconds; 2) venous pressure lower limit: 8 seconds; 3) venous pressure upper limit: 7 seconds; 4) venous pressure lower limit alarm: 2 seconds; and 5) blood leakage alarm: 19 seconds. All alarms were set off in under 20 seconds. Thus, we can conclude that a simulator system using an extracorporeal circulation system can be set to different models of dialyzers, and that the reproduced treatment scenarios can be used for simulation training.

Total internal reflectance fluorescence imaging of genetically engineered ryanodine receptor-targeted Ca2+ probes in rat ventricular myocytes.

PubMed

Pahlavan, Sara; Morad, Marin

2017-09-01

The details of cardiac Ca 2+ signaling within the dyadic junction remain unclear because of limitations in rapid spatial imaging techniques, and availability of Ca 2+ probes localized to dyadic junctions. To critically monitor ryanodine receptors' (RyR2) Ca 2+ nano-domains, we combined the use of genetically engineered RyR2-targeted pericam probes, (FKBP-YCaMP, K d =150nM, or FKBP-GCaMP6, K d =240nM) with rapid total internal reflectance fluorescence (TIRF) microscopy (resolution, ∼80nm). The punctate z-line patterns of FKBP, 2 -targeted probes overlapped those of RyR2 antibodies and sharply contrasted to the images of probes targeted to sarcoplasmic reticulum (SERCA2a/PLB), or cytosolic Fluo-4 images. FKBP-YCaMP signals were too small (∼20%) and too slow (2-3s) to detect Ca 2+ sparks, but the probe was effective in marking where Fluo-4 Ca 2+ sparks developed. FKBP-GCaMP6, on the other hand, produced rapidly decaying Ca 2+ signals that: a) had faster kinetics and activated synchronous with I Ca 3 but were of variable size at different z-lines and b) were accompanied by spatially confined spontaneous Ca 2+ sparks, originating from a subset of eager sites. The frequency of spontaneously occurring sparks was lower in FKBP-GCaMP6 infected myocytes as compared to Fluo-4 dialyzed myocytes, but isoproterenol enhanced their frequency more effectively than in Fluo-4 dialyzed cells. Nevertheless, isoproterenol failed to dissociate FKBP-GCaMP6 from the z-lines. The data suggests that FKBP-GCaMP6 binds predominantly to junctional RyR2s and has sufficient on-rate efficiency as to monitor the released Ca 2+ in individual dyadic clefts, and supports the idea that β-adrenergic agonists may modulate the stabilizing effects of native FKBP on RyR2. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioaccessible peptides released by in vitro gastrointestinal digestion of fermented goat milks.

PubMed

Moreno-Montoro, Miriam; Jauregi, Paula; Navarro-Alarcón, Miguel; Olalla-Herrera, Manuel; Giménez-Martínez, Rafael; Amigo, Lourdes; Miralles, Beatriz

2018-06-01

In this study, ultrafiltered goat milks fermented with the classical starter bacteria Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarus subsp. thermophilus or with the classical starter plus the Lactobacillus plantarum C4 probiotic strain were analyzed using ultra-high performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) and/or high performance liquid chromatography-ion trap (HPLC-IT-MS/MS). Partial overlapping of the identified sequences with regard to fermentation culture was observed. Evaluation of the cleavage specificity suggested a lower proteolytic activity of the probiotic strain. Some of the potentially identified peptides had been previously reported as angiotensin-converting enzyme (ACE) inhibitory, antioxidant, and antibacterial and might account for the in vitro activity previously reported for these fermented milks. Simulated digestion of the products was conducted in the presence of a dialysis membrane to retrieve the bioaccessible peptide fraction. Some sequences with reported physiological activity resisted digestion but were found in the non-dialyzable fraction. However, new forms released by digestion, such as the antioxidant α s1 -casein 144 YFYPQL 149 , the antihypertensive α s2 -casein 90 YQKFPQY 96 , and the antibacterial α s2 -casein 165 LKKISQ 170 , were found in the dialyzable fraction of both fermented milks. Moreover, in the fermented milk including the probiotic strain, the k-casein dipeptidyl peptidase IV inhibitor (DPP-IV) 51 INNQFLPYPY 60 as well as additional ACE inhibitory or antioxidant sequences could be identified. With the aim of anticipating further biological outcomes, quantitative structure activity relationship (QSAR) analysis was applied to the bioaccessible fragments and led to potential ACE inhibitory sequences being proposed. Graphical abstract Ultrafiltered goat milks were fermented with the classical starter bacteria (St) and with St plus the L. plantarum C4 probiotic strain. Samples were analyzed using HPLC-IT-MS/MS and UPLC-Q-TOF-MS/MS. After simulated digestion and dialysis, some of the active sequences remained and new peptides with reported beneficial activities were released.

Atropine microdialysis within or near the pre-Bötzinger Complex increases breathing frequency more during wakefulness than during NREM sleep

PubMed Central

Muere, Clarissa; Neumueller, Suzanne; Miller, Justin; Olesiak, Samantha; Hodges, Matthew R.; Pan, Lawrence

2013-01-01

Normal activity of neurons within the medullary ventral respiratory column (VRC) in or near the pre-Bötzinger Complex (preBötC) is dependent on the balance of inhibitory and excitatory neuromodulators acting at their respective receptors. The role of cholinergic neuromodulation during awake and sleep states is unknown. Accordingly, our objective herein was to test the hypotheses that attenuation of cholinergic modulation of VRC/preBötC neurons in vivo with atropine would: 1) decrease breathing frequency more while awake than during non-rapid-eye-movement (NREM) sleep and 2) increase other excitatory neuromodulators. To test these hypotheses, we unilaterally dialyzed mock cerebrospinal fluid (mCSF) or 50 mM atropine in mCSF in or near the preBötC region of adult goats during the awake (n = 9) and NREM sleep (n = 7) states. Breathing was monitored, and effluent dialysate was collected for analysis of multiple neurochemicals. Compared with dialysis of mCSF alone, atropine increased (P < 0.05) breathing frequency while awake during the day [+10 breaths (br)/min] and at night (+9 br/min) and, to a lesser extent, during NREM sleep (+5 br/min). Atropine increased (P < 0.05) effluent concentrations of serotonin (5-HT), substance P (SP), and glycine during the day and at night. When atropine was dialyzed in one preBötC and mCSF in the contralateral preBötC, 5-HT and SP increased only at the site of atropine dialysis. We conclude: 1) attenuation of a single neuromodulator results in local changes in other neuromodulators that affect ventilatory control, 2) effects of perturbations of cholinergic neuromodulation on breathing are state-dependent, and 3) interpretation of perturbations in vivo requires consideration of direct and indirect effects. PMID:23271698

Development of anion-exchange/reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry methods for the speciation of bio-available iodine and bromine from edible seaweed.

PubMed

Romarís-Hortas, Vanessa; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2012-05-04

Anion exchange high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry has been novelly applied to assess inorganic (iodide and iodate) and organic (3-iodotyrosine - MIT, and 3,5-diiodotyrosine - DIT) iodine species in a single chromatographic run. The optimized operating conditions (Dionex IonPac AS7, gradient elution with 175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase and flow rates within the 0.5-1.5 mL min(-1) range) have also been used to perform inorganic bromine speciation analysis (bromide and bromate). The developed method has been applied for determining the bio-available contents of iodine and bromine species in dialyzates from edible seaweed. Reverse phase high performance liquid chromatography (Zorbax Eclipse XDB-C8, gradient elution with 0.2% (m/m) acetic acid, and 0.2% (m/m) acetic acid in methanol, as mobile phases, and a constant flow rate of 0.75 mL min(-1)) also hyphenated with inductively coupled plasma-mass spectrometry was used to confirm the presence of organic iodine species (MIT and DIT) in the dialyzates. The verification of the presence of iodinated amino acids (MIT and DIT) in the extracts was also performed by reverse phase high performance liquid chromatography-electrospray ionization-mass spectrometry (LTQ Orbitrap). The developed methods have provided good repeatability (RSD values lower than 10% for both anion exchange and reverse phase separations) and analytical recoveries within the 90-105% range for all cases. The in vitro bio-availability method consisted of a simulated gastric and an intestinal digestion/dialysis (10 kDa molecular weight cut-off - MWCO) two-stage procedure. Iodide and MIT were the main bio-available species quantified, whereas bromide was the major bromine species found in the extracts. Copyright © 2012 Elsevier B.V. All rights reserved.

Matrix metalloproteinases and soluble Fas/FasL system as novel regulators of apoptosis in children and young adults on chronic dialysis.

PubMed

Musiał, Kinga; Zwolińska, Danuta

2011-07-01

The system of membrane receptor Fas and its ligand FasL compose one of the main pathways triggering apoptosis. However, the role of their soluble forms has not been clarified yet. Although sFasL can be converted from the membrane-bound form by matrix metalloproteinases (MMPs), there are no data on relations between sFas/sFasL, MMPs and their tissue inhibitors (TIMPs) in patients on chronic dialysis--neither children nor adults. The aim of our study was to evaluate serum concentrations of sFas, sFasL, and their potential regulators (MMP-2, MMP-7, MMP-9, TIMP-1, TIMP-2), in children and young adults chronically dialyzed. Twenty-two children on automated peritoneal dialysis (APD), 19 patients on hemodialysis (HD) and 30 controls were examined. Serum concentrations of sFas, sFasL, MMPs and TIMPs were assessed by ELISA. Median values of sFas, sFasL, sFas/sFasL ratio, MMP-2, MMP-7, MMP-9, TIMP-1 and TIMP-2 were significantly elevated in all dialyzed patients vs. controls, the highest values being observed in subjects on HD. A single HD session caused the decrease in values of all parameters to the levels below those seen in children on APD. Regression analysis revealed that MMP-7 and TIMP-1 were the best predictors of sFas and sFasL concentrations. Children and young adults on chronic dialysis are prone to sFas/sFasL system dysfunction, more pronounced in patients on hemodialysis. The correlations between sFas/sFasL and examined enzymes suggest that MMPs and TIMPs take part in the regulation of cell death in the pediatric population on chronic dialysis, triggering both anti- (sFas) and pro-apoptotic (sFasL) mechanisms.

Polymethylmethacrylate membrane with a series of serendipity.

PubMed

Sakai, Yoshitada

2011-01-01

Forty years have passed since the polymethylmethacrylate (PMMA) membrane was first developed. This article reviews its history and explains its longevity. The membrane was developed through application of a stereocomplex phenomenon that is observed upon mixture of isotactic and syndiotactic PMMA polymers. Filtryzer(TM) B1 and B2 were approved in Japan in 1977. B1 was the pioneer high-performance membrane model and B2 was a model that simulated a low-flux cellulosic membrane. The development of B1 led to the development of the dialysis machine with an ultrafiltration rate (UFR)-controlling function because the UFR of B1 was too high to control using transmembrane pressure control. B1 was used not only as a dialyzer but also as a hemodiafilter by combination with a UFR controller. Biocompatibility of the dialysis membrane, complement activation and/or transient leukopenia was studied with B2. Cooperative studies between Niigata University and Toray resulted in Gejyo's finding regarding the harmfulness of β(2)-microglobulin (BMG). Long-term follow-up of patients dialyzed using the BK membrane revealed that plasma BMG levels were significantly low and that the occurrence ratio of carpal tunnel syndrome was suppressed. These results were obtained by the adsorptive removal of BMG onto a PMMA membrane. Several papers have discussed new aspects in succession mainly based on clinical experiences that were not aimed at a development stage, i.e. they were kinds of serendipity. For the BK-F membrane with the largest pore size, this includes anemia and removal or modification of furancarboxylic acid, homocysteine, pentosidine and soluble CD40. For the BG membrane with a slightly anionic component, this includes pruritus and removal of free immunoglobulin light chains. Even patients' prognoses may be modified by the use of PMMA membrane. The mechanisms of these findings have been clarified bit by bit and the membrane will further open new frontiers in dialysis treatment. Copyright © 2011 S. Karger AG, Basel.

The critical success factors and impact of prior knowledge to nursing students when transferring nursing knowledge during nursing clinical practise.

PubMed

Tsai, Ming-Tien; Tsai, Ling-Long

2005-11-01

Nursing practise plays an important role in transferring nursing knowledge to nursing students. From the related literature review, prior knowledge will affect how learners gain new knowledge. There has been no direct examination of the prior knowledge interaction effect on students' performance and its influence on nursing students when evaluating the knowledge transfer success factors. This study explores (1) the critical success factors in transferring nursing knowledge, (2) the impact of prior knowledge when evaluating the success factors for transferring nursing knowledge. This research utilizes in-depth interviews to probe the initial success factor phase. A total of 422 valid questionnaires were conducted by the authors. The data were analysed by comparing the mean score and t-test between two groups. Seventeen critical success factors were identified by the two groups of students. Twelve items were selected to examine the diversity in the two groups. Students with prior knowledge were more independent than the other group. They also preferred self-directed learning over students without prior knowledge. Students who did not have prior knowledge were eager to take every opportunity to gain experience and more readily adopted new knowledge.

The effect of twisted-tape width on heat transfer and pressure drop for fully developed laminar flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakroun, W.M.; Al-Fahed, S.F.

1996-07-01

A series of experiments was conducted to study the effect of twisted-tape width on the heat transfer and pressure drop with laminar flow in tubes. Data for three twisted-tape wavelengths, each with five different widths, have been collected with constant wall temperature boundary condition. Correlations for the friction factor and Nusselt number are also available. The correlations predict the experimental data to within 10 to 15 percent for the heat transfer and friction factor, respectively. The presence of the twisted tape has caused the friction factor to increase by a factor of 3 to 7 depending on Reynolds number andmore » the twisted-tape geometry. Heat transfer results have shown an increase of 1.5 to 3 times that of plain tubes depending on the flow conditions and the twisted-tape geometry. The width shows no effect on friction factor and heat transfer in the low range of Reynolds number but has a more pronounced effect on heat transfer at the higher range of Reynolds number. It is recommended to use loose-fit tapes for low Reynolds number flows instead of tight-fit in the design of heat exchangers because they are easier to install and remove for cleaning purposes.« less

Perception of Transfer Climate Factors in the Macro and Micro Organizational Work Environment

ERIC Educational Resources Information Center

Diggs, Byron Kenneth

2011-01-01

This qualitative study was designed to provide insight on the perceived transfer climate factors in the macro and micro organizational work environment that may influence an employee's willingness to transfer what was learned in a training program to the job. More specifically, the purpose of the study was to delineate descriptive patterns and…

A Probe into the Negative Writing Transfer of Chinese College Students

ERIC Educational Resources Information Center

He, Xiaojun; Niao, Lina

2015-01-01

Although Chinese college students have studied English for many years, they still have much difficulty in writing a good paper. There are many factors resulting in their inability to write well, such as students' lack of vocabulary, having a poor knowledge of grammar, language transfer, and so on. But, of these factors, the negative transfer of…

Effect of aerated concrete blockwork joints on the heat transfer performance uniformity

NASA Astrophysics Data System (ADS)

Pukhkal, Viktor; Murgul, Vera

2018-03-01

Analysis of data on the effect of joints of the aerated concrete blocks on the heat transfer uniformity of exterior walls was carried out. It was concluded, that the values of the heat transfer performance uniformity factor in the literature sources were obtained for the regular fragment of a wall construction by approximate addition of thermal conductivities. Heat flow patterns for the aerated concrete exterior walls amid different values of the thermal conductivity factors and design ambient air temperature of -26 °C were calculated with the use of "ELCUT" software for modelling of thermal patterns by finite element method. There were defined the values for the heat transfer performance uniformity factor, reduced total thermal resistance and heat-flux density for the exterior walls. The calculated values of the heat transfer performance uniformity factors, as a function of the coefficient of thermal conductivity of aerated concrete blocks, differ from the known data by a more rigorous thermal and physical substantiation.

Experimental determination of heat transfer coefficients in roll bite and air cooling for computer simulations of 1100 MPa carbon steel rolling

NASA Astrophysics Data System (ADS)

Leinonen, Olli; Ilmola, Joonas; Seppälä, Oskari; Pohjonen, Aarne; Paavola, Jussi; Koskenniska, Sami; Larkiola, Jari

2018-05-01

In modeling of hot rolling pass schedules the heat transfer phenomena have to be known. Radiation to ambient, between rolls and a steel slab as well as heat transfer in contacts must be considered to achieve accurate temperature distribution and thereby accurate material behavior in simulations. Additional heat is generated by friction between the slab and the work roll and by plastic deformation. These phenomena must be taken into account when the effective heat transfer coefficient is determined from experimental data. In this paper we determine the effective heat transfer coefficient at the contact interface and emissivity factor of slab surface for 1100MPa strength carbon steel for hot rolling simulations. Experimental pilot rolling test were carried out and slab temperatures gathered right below the interface and at the mid thickness of the slab. Emissivity factor tests were carried out in the same manner but without rolling. Experimental data is utilized to derive contact heat transfer coefficient at the interface and emissivity factor of slab surface. Pilot rolling test is reproduced in FE-analysis to further refine the heat transfer coefficient and emissivity factor. Material mechanical properties at rolling temperatures were determined by Gleeble™ thermo-mechanical simulator and IDS thermodynamic-kinetic-empirical software.

A Nuanced Look at Women in STEM Fields at Two-Year Colleges: Factors That Shape Female Students' Transfer Intent.

PubMed

Wang, Xueli; Chan, Hsun-Yu; Soffa, Sara Jimenez; Nachman, Brett Ranon

2017-01-01

In this study, we explored the relationship between the intent to transfer upward and a set of motivational, contextual, and socio-demographic background factors among 696 female students beginning in science, technology, engineering, and mathematics (STEM) programs or courses at two-year colleges in a Midwestern state. Drawing upon survey data and administrative records, our multinomial logistic regression analysis revealed that students' math and science self-efficacy beliefs, as well as transfer-oriented interaction, were significant and positive predictors for their intent to transfer into STEM fields as opposed to having no intent to transfer. In addition, the association between transfer intent and these key motivational and contextual factors was moderated by students' racial/ethnic backgrounds, marital status, and childcare obligations. For example, despite the positive relationship between transfer-oriented interaction and the intention to transfer into STEM fields, Black women were less likely to have intent to transfer into STEM fields than White students until Black students reported a moderate level of transfer-oriented interaction. Conversely, Hispanic students were more likely to report intent to transfer into STEM fields than their White peers, even when Hispanic students reported a relatively low level of engagement in transfer-oriented interaction. These and other reported findings bear important and nuanced implications as policymakers, educators, and researchers continue to discover ways to better support women's educational pathways and success in STEM fields at and through two-year colleges.

A Nuanced Look at Women in STEM Fields at Two-Year Colleges: Factors That Shape Female Students' Transfer Intent

PubMed Central

Wang, Xueli; Chan, Hsun-yu; Soffa, Sara Jimenez; Nachman, Brett Ranon

2017-01-01

In this study, we explored the relationship between the intent to transfer upward and a set of motivational, contextual, and socio-demographic background factors among 696 female students beginning in science, technology, engineering, and mathematics (STEM) programs or courses at two-year colleges in a Midwestern state. Drawing upon survey data and administrative records, our multinomial logistic regression analysis revealed that students' math and science self-efficacy beliefs, as well as transfer-oriented interaction, were significant and positive predictors for their intent to transfer into STEM fields as opposed to having no intent to transfer. In addition, the association between transfer intent and these key motivational and contextual factors was moderated by students' racial/ethnic backgrounds, marital status, and childcare obligations. For example, despite the positive relationship between transfer-oriented interaction and the intention to transfer into STEM fields, Black women were less likely to have intent to transfer into STEM fields than White students until Black students reported a moderate level of transfer-oriented interaction. Conversely, Hispanic students were more likely to report intent to transfer into STEM fields than their White peers, even when Hispanic students reported a relatively low level of engagement in transfer-oriented interaction. These and other reported findings bear important and nuanced implications as policymakers, educators, and researchers continue to discover ways to better support women's educational pathways and success in STEM fields at and through two-year colleges. PMID:28220102

Isolation and Purification of Antibiotic Material from Physarum gyrosum

PubMed Central

Schroeder, H. R.; Mallette, M. F.

1973-01-01

The myxomycete Physarum gyrosum was cultured in its plasmodial stage on agar plates containing 0.025 M phosphate buffer at pH 6.5, 2% bakers' yeast, and 0.2% glucose and was supplemented with live Escherichia coli. Extracts of these plasmodia contained several antibiotic substances. Antibiotic materials were partially purified by dialysis of the agar medium-mold mixture, evaporation of the dialyzate, and butanol extraction of the residue. Further purification in two paper and two thin-layer chromatographic systems gave one product which was pure in six thin-layer chromatographic systems. Antibiotic activity against some gram-positive and gram-negative bacteria and yeasts was demonstrated with partially purified extracts and a paper-chromatographically separated fraction. One pure antibiotic was effective against Bacillus cereus. PMID:4799591

[The hypotriglyceridemic action of the combination of L-carnitine + simvastatin vs. L-carnitine and vs. simvastatin].

PubMed

Savica, V; Bellinghieri, G; Lamanna, F

1992-01-01

Previous studies had determined the role played by L-carnitine and simvastatin in the treatment of altered lipidemia in dialyzed patients with chronic uremia. The authors carried out a study on the above substances either singly or together administered to the same patients with chronic uremia in hemodialysis. This study was aimed at demonstrating the possible synergic normolipidemic action of both substances in comparison with their single administration, because their different mechanism of action could be metabolically enhanced. The obtained results demonstrated that the therapeutic association proposed is preferable to the use of the single substances. Moreover, a higher and more rapid normolipidemic effect was obtained after using L-carnitina associated with simvastatin with respect to the separated substances.

Predictive modeling of cardiovascular complications in incident hemodialysis patients.

PubMed

Ion Titapiccolo, J; Ferrario, M; Barbieri, C; Marcelli, D; Mari, F; Gatti, E; Cerutti, S; Smyth, P; Signorini, M G

2012-01-01

The administration of hemodialysis (HD) treatment leads to the continuous collection of a vast quantity of medical data. Many variables related to the patient health status, to the treatment, and to dialyzer settings can be recorded and stored at each treatment session. In this study a dataset of 42 variables and 1526 patients extracted from the Fresenius Medical Care database EuCliD was used to develop and apply a random forest predictive model for the prediction of cardiovascular events in the first year of HD treatment. A ridge-lasso logistic regression algorithm was then applied to the subset of variables mostly involved in the prediction model to get insights in the mechanisms underlying the incidence of cardiovascular complications in this high risk population of patients.

Application of in vitro bioaccessibility and bioavailability methods for calcium, carotenoids, folate, iron, magnesium, polyphenols, zinc, and vitamins B6, B12, D, and E

PubMed Central

Etcheverry, Paz; Grusak, Michael A.; Fleige, Lisa E.

2012-01-01

A review of in vitro bioaccessibility and bioavailability methods for polyphenols and selected nutrients is presented. The review focuses on in vitro solubility, dialyzability, the dynamic gastrointestinal model (TIM)™, and Caco-2 cell models, the latter primarily for uptake and transport, and a discussion of how these methods have been applied to generate data for a range of nutrients, carotenoids, and polyphenols. Recommendations are given regarding which methods are most justified for answering bioaccessibility or bioavailability related questions for specific nutrients. The need for more validation studies in which in vivo results are compared to in vitro results is also discussed. PMID:22934067

PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

PubMed Central

Price, Winston H.

1949-01-01

1. A non-dialyzable fraction from fresh bakers' yeast stimulates the formation of S. muscae virus in cells in synthetic medium in the log phase of multiplication. 2. A similar fraction was not found in calf thymus, pancreas, or liver. 3. The active substance in this fraction has been partially purified. 4. This substance is taken up by the cells. In the absence of virus the added substance is metabolized to a form no longer available for virus formation. 5. A purified yeast fraction, which stimulates adaptive enzyme formation in yeast, has been found to stimulate virus formation in the S. muscae system. 6. The similarities between the yeast fraction that stimulates adaptive enzyme formation and the yeast fraction that stimulates virus formation are discussed. PMID:18123312

Fundamental Characteristics of the Newly Developed ATA™ Membrane Dialyzer.

PubMed

Sunohara, Takashi; Masuda, Toshiaki

2017-01-01

Dialysis membranes are often made from synthetic polymers, such as polysulfone. However, membranes made from cellulose triacetate have superior biocompatibility and have been used since the 1980s. On-line hemodiafiltration treatment accompanied by massive fluid replacement is increasingly being used in Europe and Japan, but cellulose triacetate is not suitable for this treatment. Our newly developed asymmetric triacetate membrane, the ATA™ membrane, substantially improved the filtration properties and blood compatibility because of the asymmetric structure and smooth surface of this cellulose acetate membrane. Key Message: The ATA membrane maintains its high permeability even after massive filtration and shows less temporal variation in its permeation performance, lower protein adsorption, and superior biocompatibility compared with conventional membranes. © 2017 S. Karger AG, Basel.

The Impact of Workplace Support and Identity on Training Transfer: A Case Study of Drug and Alcohol Safety Training in Australia

ERIC Educational Resources Information Center

Pidd, Ken

2004-01-01

Previous research has indicated that the transfer climate of work organisations is an important factor in determining the degree to which knowledge, skills and abilities gained in training transfer to the workplace. In particular, workplace social support from supervisors and coworkers is consistently cited as an important factor that can…

Controls and variability of solute and sedimentary fluxes in Arctic and sub-Arctic Environments

NASA Astrophysics Data System (ADS)

Dixon, John

2015-04-01

Six major factors consistently emerge as controls on the spatial and temporal variability in sediment and solute fluxes in cold climates. They are climatic, geologic, physiographic or relief, biologic, hydrologic, and regolith factors. The impact of these factors on sediment and solute mass transfer in Arctic and sub-Arctic environments is examined. Comparison of non-glacierized Arctic vs. subarctic drainage basins reveals the effects of these controls. All drainage basins exhibit considerable variability in rates of sediment and solute fluxes. For the non-glacierized drainage basins there is a consistent increase in sediment mass transfer by slope processes and fluvial processes as relief increases. Similarly, a consistent increase in sediment mass transfer by slope and fluvial processes is observed as total precipitation increases. Similar patterns are also observed with respect to solute transport and relief and precipitation. Lithologic factors are most strongly observed in the contrast between volcanic vs. plutonic igneous bedrock substrates. Basins underlain by volcanic rocks display greater mass transfers than those underlain by plutonic rocks. Biologic influences are most strongly expressed by variations in extent of vegetation cover and the degree of human interference, with human impacted basins generating greater fluxes. For glacierized basins the fundamental difference to non-glacierized basins is an overall increase in mean annual mass transfers of sediment and a generally smaller magnitude solute transfer. The principal role of geology is observed with respect to lithology. Catchments underlain by limestone demonstrate substantially greater solute mass transfers than sediment transfer. The influence of relief is seen in the contrast in mass transfers between upland and lowland drainage basins with upland basins generating greater sediment and solute transfers than lowland basins. For glacierized basins the effects of biology and regolith appear to be largely overridden by the hydrologic impacts of glacierization.

Satisfaction Levels and Factors Influencing Satisfaction With Use of a Social App for Neonatal and Pediatric Patient Transfer Information Systems: A Questionnaire Study Among Doctors

PubMed Central

Choi, Iee; Kim, Sun Jun; Cho, Soo Chul; Kim, Il Nyeo

2016-01-01

Background The treatment of neonatal and pediatric patients is limited to certain medical institutions depending on treatment difficulty. Effective patient transfers are necessary in situations where there are limited medical resources. In South Korea, the government has made a considerable effort to establish patient transfer systems using various means, such as websites, telephone, and so forth. However, in reality, the effort has not yet been effective. Objective In this study, we ran a patient transfer information system using a social app for effective patient transfer. We analyzed the results, satisfaction levels, and the factors influencing satisfaction. Methods Naver Band is a social app and mobile community application which in Korea is more popular than Facebook. It facilitates group communication. Using Naver Band, two systems were created: one by the Neonatal Intensive Care Unit and the other by the Department of Pediatrics at Chonbuk National University Children's Hospital, South Korea. The information necessary for patient transfers was provided to participating obstetricians (n=51) and pediatricians (n=90). We conducted a survey to evaluate the systems and reviewed the results retrospectively. Results The number of patients transferred was reported to increase by 65% (26/40) obstetricians and 40% (23/57) pediatricians. The time taken for transfers was reported to decrease by 72% (29/40) obstetricians and 59% (34/57) pediatricians. Satisfaction was indicated by 83% (33/40) obstetricians and 89% (51/57) pediatricians. Regarding factors influencing satisfaction, the obstetricians reported communication with doctors in charge (P=.03) and time reduction during transfers (P=.02), whereas the pediatricians indicated review of the diagnosis and treatment of transferred patients (P=.01) and the time reduction during transfers (P=.007). Conclusions The users were highly satisfied and different users indicated different factors of satisfaction. This finding implies that users’ requirements should be accommodated in future developments of patient transfer information systems. PMID:27492978

Satisfaction Levels and Factors Influencing Satisfaction With Use of a Social App for Neonatal and Pediatric Patient Transfer Information Systems: A Questionnaire Study Among Doctors.

PubMed

Choi, Iee; Kim, Jin Kyu; Kim, Sun Jun; Cho, Soo Chul; Kim, Il Nyeo

2016-08-04

The treatment of neonatal and pediatric patients is limited to certain medical institutions depending on treatment difficulty. Effective patient transfers are necessary in situations where there are limited medical resources. In South Korea, the government has made a considerable effort to establish patient transfer systems using various means, such as websites, telephone, and so forth. However, in reality, the effort has not yet been effective. In this study, we ran a patient transfer information system using a social app for effective patient transfer. We analyzed the results, satisfaction levels, and the factors influencing satisfaction. Naver Band is a social app and mobile community application which in Korea is more popular than Facebook. It facilitates group communication. Using Naver Band, two systems were created: one by the Neonatal Intensive Care Unit and the other by the Department of Pediatrics at Chonbuk National University Children's Hospital, South Korea. The information necessary for patient transfers was provided to participating obstetricians (n=51) and pediatricians (n=90). We conducted a survey to evaluate the systems and reviewed the results retrospectively. The number of patients transferred was reported to increase by 65% (26/40) obstetricians and 40% (23/57) pediatricians. The time taken for transfers was reported to decrease by 72% (29/40) obstetricians and 59% (34/57) pediatricians. Satisfaction was indicated by 83% (33/40) obstetricians and 89% (51/57) pediatricians. Regarding factors influencing satisfaction, the obstetricians reported communication with doctors in charge (P=.03) and time reduction during transfers (P=.02), whereas the pediatricians indicated review of the diagnosis and treatment of transferred patients (P=.01) and the time reduction during transfers (P=.007). The users were highly satisfied and different users indicated different factors of satisfaction. This finding implies that users' requirements should be accommodated in future developments of patient transfer information systems.

The Barriers and Facilitators to Transfer of Ultrasound-Guided Central Venous Line Skills From Simulation to Practice: Exploring Perceptions of Learners and Supervisors.

PubMed

Mema, Briseida; Harris, Ilene

2016-01-01

PHENOMENON: Ultrasound-guided central venous line insertion is currently the standard of care. Randomized controlled trials and systematic reviews show that simulation is superior to apprenticeship training. The purpose of this study is to explore, from the perspectives of participants in a simulation-training program, the factors that help or hinder the transfer of skills from simulation to practice. Purposeful sampling was used to select and study the experience and perspective of novice fellows after they had completed simulation training and then performed ultrasound-guided central venous line in practice. Seven novice pediatric intensive care unit fellows and six supervising faculty in a university-affiliated academic center in a large urban city were recruited between September 2012 and January 2013. We conducted a qualitative study using semistructured interviews as our data source, employing a constructivist, grounded theory methodology. Both curricular and real-life factors influence the transfer of skills from simulation to practice and the overall performance of trainees. Clear instructions, the opportunity to practice to mastery, one-on-one observation with feedback, supervision, and further real-life experiences were perceived as factors that facilitated the transfer of skills. Concern for patient welfare, live trouble shooting, complexity of the intensive care unit environment, and the procedure itself were perceived as real-life factors that hindered the transfer of skills. Insights: As more studies confirm the superiority of simulation training versus apprenticeship training for initial student learning, the faculty should gain insight into factors that facilitate and hinder the transfer of skills from simulation to bedside settings and impact learners' performances. As simulation further augments clinical learning, efforts should be made to modify the curricular and bedside factors that facilitate transfer of skills from simulation to practice settings.

Factor IX expression in skeletal muscle of a severe hemophilia B patient 10 years after AAV-mediated gene transfer.

PubMed

Buchlis, George; Podsakoff, Gregory M; Radu, Antonetta; Hawk, Sarah M; Flake, Alan W; Mingozzi, Federico; High, Katherine A

2012-03-29

In previous work we transferred a human factor IX-encoding adeno-associated viral vector (AAV) into skeletal muscle of men with severe hemophilia B. Biopsy of injected muscle up to 1 year after vector injection showed evidence of gene transfer by Southern blot and of protein expression by IHC and immunofluorescent staining. Although the procedure appeared safe, circulating F.IX levels remained subtherapeutic (< 1%). Recently, we obtained muscle tissue from a subject injected 10 years earlier who died of causes unrelated to gene transfer. Using Western blot, IHC, and immunofluorescent staining, we show persistent factor IX expression in injected muscle tissue. F.IX transcripts were detected in injected skeletal muscle using RT-PCR, and isolated whole genomic DNA tested positive for the presence of the transferred AAV vector sequence. This is the longest reported transgene expression to date from a parenterally administered AAV vector, with broad implications for the future of muscle-directed gene transfer.

Factor IX expression in skeletal muscle of a severe hemophilia B patient 10 years after AAV-mediated gene transfer

PubMed Central

Buchlis, George; Podsakoff, Gregory M.; Radu, Antonetta; Hawk, Sarah M.; Flake, Alan W.; Mingozzi, Federico

2012-01-01

In previous work we transferred a human factor IX–encoding adeno-associated viral vector (AAV) into skeletal muscle of men with severe hemophilia B. Biopsy of injected muscle up to 1 year after vector injection showed evidence of gene transfer by Southern blot and of protein expression by IHC and immunofluorescent staining. Although the procedure appeared safe, circulating F.IX levels remained subtherapeutic (< 1%). Recently, we obtained muscle tissue from a subject injected 10 years earlier who died of causes unrelated to gene transfer. Using Western blot, IHC, and immunofluorescent staining, we show persistent factor IX expression in injected muscle tissue. F.IX transcripts were detected in injected skeletal muscle using RT-PCR, and isolated whole genomic DNA tested positive for the presence of the transferred AAV vector sequence. This is the longest reported transgene expression to date from a parenterally administered AAV vector, with broad implications for the future of muscle-directed gene transfer. PMID:22271447

Risk Transfer Formula for Individual and Small Group Markets Under the Affordable Care Act

PubMed Central

Pope, Gregory C; Bachofer, Henry; Pearlman, Andrew; Kautter, John; Hunter, Elizabeth; Miller, Daniel; Keenan, Patricia

2014-01-01

The Affordable Care Act provides for a program of risk adjustment in the individual and small group health insurance markets in 2014 as Marketplaces are implemented and new market reforms take effect. The purpose of risk adjustment is to lessen or eliminate the influence of risk selection on the premiums that plans charge. The risk adjustment methodology includes the risk adjustment model and the risk transfer formula. This article is the third of three in this issue of the Medicare & Medicaid Research Review that describe the ACA risk adjustment methodology and focuses on the risk transfer formula. In our first companion article, we discussed the key issues and choices in developing the methodology. In our second companion paper, we described the risk adjustment model that is used to calculate risk scores. In this article we present the risk transfer formula. We first describe how the plan risk score is combined with factors for the plan allowable premium rating, actuarial value, induced demand, geographic cost, and the statewide average premium in a formula that calculates transfers among plans. We then show how each plan factor is determined, as well as how the factors relate to each other in the risk transfer formula. The goal of risk transfers is to offset the effects of risk selection on plan costs while preserving premium differences due to factors such as actuarial value differences. Illustrative numerical simulations show the risk transfer formula operating as anticipated in hypothetical scenarios. PMID:25352994

Preliminary Diffusive Clearance of Silicon Nanopore Membranes in a Parallel Plate Configuration for Renal Replacement Therapy

PubMed Central

Kim, Steven; Heller, James; Iqbal, Zohora; Kant, Rishi; Kim, Eun Jung; Durack, Jeremy; Saeed, Maythem; Do, Loi; Hetts, Steven; Wilson, Mark; Brakeman, Paul; Fissell, William H.; Roy, Shuvo

2015-01-01

Silicon nanopore membranes (SNM) with compact geometry and uniform pore size distribution have demonstrated a remarkable capacity for hemofiltration. These advantages could potentially be used for hemodialysis. Here we present an initial evaluation of the SNM’s mechanical robustness, diffusive clearance, and hemocompatibility in a parallel plate configuration. Mechanical robustness of the SNM was demonstrated by exposing membranes to high flows (200ml/min) and pressures (1,448mmHg). Diffusive clearance was performed in an albumin solution and whole blood with blood and dialysate flow rates of 25ml/min. Hemocompatibility was evaluated using scanning electron microscopy and immunohistochemistry after 4-hours in an extra-corporeal porcine model. The pressure drop across the flow cell was 4.6mmHg at 200ml/min. Mechanical testing showed that SNM could withstand up to 775.7mmHg without fracture. Urea clearance did not show an appreciable decline in blood versus albumin solution. Extra-corporeal studies showed blood was successfully driven via the arterial-venous pressure differential without thrombus formation. Bare silicon showed increased cell adhesion with a 4.1 fold increase and 1.8 fold increase over polyethylene-glycol (PEG)-coated surfaces for tissue plasminogen factor (t-PA) and platelet adhesion (CD-41), respectively. These initial results warrant further design and development of a fully scaled SNM-based parallel plate dialyzer for renal replacement therapy. PMID:26692401

Conformity Scores Differentiate Older Hemodialyzed Patients and Patients with Continuous Peritoneal Dialysis

PubMed Central

Nowak, Zbigniew; Laudanski, Krzysztof

2016-01-01

Background Conformity is a psychological variable related to the propensity of an individual to match his or her behavior and opinion to the perceived social and cultural norm, even if these do not represent the true beliefs of the person. The aim of the present study was to investigate whether the psychological variable of conformity is different in two distinct modes of renal replacement therapy (RRT) in end-stage renal disease (ESRD). Material/Methods A total of 56 hemodialyzed patients (HD group), 45 continuous ambulatory peritoneal dialysis patients (CAPD group) and 62 healthy volunteers (CONTR group) were enrolled in the study. The Social Appraisal Questionnaire (SAQ) was employed, and chart review was performed to collect clinical data. Results When age was not a factor, the conformity measure was significantly higher in the HD group compared with the CAPD and CONTR groups. The lowest conformity was found in healthy participants who were asked to imagine an acute medical problem. The highest conformity was found in older HD and CAPD patients. Conclusions Being chronically ill and having adaptable views may be more favorable traits for coping with ESRD in dialyzed patients, especially in elderly HD patients. On the other hand, conformity can be deleterious if CAPD patients decide to overlook certain facts or not confront the medical aspects of their condition. PMID:27886156

High Intracellular Chloride Slows the Decay of Glycinergic Currents

PubMed Central

Pitt, Samantha J.; Sivilotti, Lucia G.; Beato, Marco

2009-01-01

The time course of currents mediated by native and recombinant glycine receptors was examined with a combination of rapid agonist applications to outside-out patches and single-channel recording. The deactivation time constant of currents evoked by brief, saturating pulses of glycine is profoundly affected by the chloride concentration on the intracellular side of the cell membrane. Deactivation was threefold slower when intracellular chloride was increased from a low level (10 mm), similar to that observed in living mature neurons, to 131 mm (“symmetrical” chloride, often used in pipette internal solutions). Single-channel analysis revealed that high chloride has its greatest effect on the channel closing rate, slowing it by a factor of 2 compared with the value we estimated in the cell-attached mode (in which the channels are at physiological intracellular chloride concentrations). The same effect of chloride was observed when glycinergic evoked synaptic currents were recorded from juvenile rat spinal motoneurons in vitro, because the decay time constant was reduced from ∼7ms to ∼3 ms when cells were dialyzed with 10 mm chloride intracellular recording solution. Our results indicate that the time course of glycinergic synaptic inhibition in intact neurons is much faster than is estimated by measurements in symmetrical chloride and can be modulated by changes in intracellular chloride concentration in the range that can occur in physiological or pathological conditions. PMID:18987182

Transferability of economic evaluations of medical technologies: a new technology for orthopedic surgery.

PubMed

Steuten, Lotte; Vallejo-Torres, Laura; Young, Terry; Buxton, Martin

2008-05-01

Transferring results of economic evaluations across countries or jurisdictions can potentially save scarce evaluation resources while helping to make market access and reimbursement decisions in a timely fashion. This article points out why transferring results of economic evaluations is particularly important in the field of medical technologies. It then provides an overview of factors that are previously identified in the literature as affecting transferability of economic evaluations, as well as methods for transferring results in a scientifically sound way. As the current literature almost exclusively relates to transferability of pharmacoeconomic evaluations, this article highlights those factors and methodologies that are of particular relevance to transferring medical technology assessments. Considering the state-of-the-art literature and a worked, real life, example of transferring an economic evaluation of a product used in orthopedic surgery, we provide recommendations for future work in this important area of medical technology assessment.

Local convective heat transfer coefficient and friction factor of CuO/water nanofluid in a microchannel heat sink

NASA Astrophysics Data System (ADS)

Chabi, A. R.; Zarrinabadi, S.; Peyghambarzadeh, S. M.; Hashemabadi, S. H.; Salimi, M.

2017-02-01

Forced convective heat transfer in a microchannel heat sink (MCHS) using CuO/water nanofluids with 0.1 and 0.2 vol% as coolant was investigated. The experiments were focused on the heat transfer enhancement in the channel entrance region at Re < 1800. Hydraulic performance of the MCHS was also estimated by measuring friction factor and pressure drop. Results showed that higher convective heat transfer coefficient was obtained at the microchannel entrance. Maximum enhancement of the average heat transfer coefficient compared with deionized water was about 40 % for 0.2 vol% nanofluid at Re = 1150. Enhancement of the convective heat transfer coefficient of nanofluid decreased with further increasing of Reynolds number.

Time-fixed rendezvous by impulse factoring with an intermediate timing constraint. [for transfer orbits

NASA Technical Reports Server (NTRS)

Green, R. N.; Kibler, J. F.; Young, G. R.

1974-01-01

A method is presented for factoring a two-impulse orbital transfer into a three- or four-impulse transfer which solves the rendezvous problem and satisfies an intermediate timing constraint. Both the time of rendezvous and the intermediate time of a alinement are formulated as any element of a finite sequence of times. These times are integer multiples of a constant plus an additive constant. The rendezvous condition is an equality constraint, whereas the intermediate alinement is an inequality constraint. The two timing constraints are satisfied by factoring the impulses into collinear parts that vectorially sum to the original impulse and by varying the resultant period differences and the number of revolutions in each orbit. Five different types of solutions arise by considering factoring either or both of the two impulses into two or three parts with a limit for four total impulses. The impulse-factoring technique may be applied to any two-impulse transfer which has distinct orbital periods.

Examining the Factor Structure and Predictive Ability of the German-Version of the Learning Transfer Systems Inventory

ERIC Educational Resources Information Center

Bates, Reid; Kauffeld, Simone; Holton, Elwood F., III

2007-01-01

Purpose: The purpose of this research is to examine the construct and predictive ability of a German version of the Learning Transfer Systems Inventory (GLTSI), an instrument designed to assess a constellation of 16 factors known to influence the transfer of training in work settings. Design/methodology/approach: The survey data for this study was…

Applying a Danish Version of the Learning Transfer System Inventory and Testing It for Different Types of Education

ERIC Educational Resources Information Center

Soerensen, Peter; Stegeager, Nikolaj; Bates, Reid

2017-01-01

The purpose of this study was to answer two research questions. First, will an exploratory factor analysis of a Danish version of the Learning Transfer System Inventory (LTSI) result in a factor structure which is consistent with the original American LTSI factor structure? Second, does the mean score in the factor analysis vary in a statistically…

Lithium Poisoning.

PubMed

Baird-Gunning, Jonathan; Lea-Henry, Tom; Hoegberg, Lotte C G; Gosselin, Sophie; Roberts, Darren M

2017-05-01

Lithium is a commonly prescribed treatment for bipolar affective disorder. However, treatment is complicated by lithium's narrow therapeutic index and the influence of kidney function, both of which increase the risk of toxicity. Therefore, careful attention to dosing, monitoring, and titration is required. The cause of lithium poisoning influences treatment and 3 patterns are described: acute, acute-on-chronic, and chronic. Chronic poisoning is the most common etiology, is usually unintentional, and results from lithium intake exceeding elimination. This is most commonly due to impaired kidney function caused by volume depletion from lithium-induced nephrogenic diabetes insipidus or intercurrent illnesses and is also drug-induced. Lithium poisoning can affect multiple organs; however, the primary site of toxicity is the central nervous system and clinical manifestations vary from asymptomatic supratherapeutic drug concentrations to clinical toxicity such as confusion, ataxia, or seizures. Lithium poisoning has a low mortality rate; however, chronic lithium poisoning can require a prolonged hospital length of stay from impaired mobility and cognition and associated nosocomial complications. Persistent neurological deficits, in particular cerebellar, are described and the incidence and risk factors for its development are poorly understood, but it appears to be uncommon in uncomplicated acute poisoning. Lithium is readily dialyzable, and rationale support extracorporeal treatments to reduce the risk or the duration of toxicity in high-risk exposures. There is disagreement in the literature regarding factors that define patients most likely to benefit from treatments that enhance lithium elimination, including specific plasma lithium concentration thresholds. In the case of extracorporeal treatments, there are observational data in its favor, without evidence from randomized controlled trials (none have been performed), which may lead to conservative practices and potentially unnecessary interventions in some circumstances. More data are required to define the risk-benefit of extracorporeal treatments and their use (modality, duration) in the management of lithium poisoning.

Convective heat transfer from circular cylinders located within perforated cylindrical shrouds

NASA Technical Reports Server (NTRS)

Daryabeigi, K.; Ash, R. L.

1986-01-01

The influence of perforated cylindrical shrouds on the convective heat transfer to circular cylinders in transverse flow has been studied experimentally. Geometries studied were similar to those used in industrial platinum resistance thermometers. The influence of Reynolds number, ventilation factor (ratio of the open area to the total surface area of shroud), radius ratio (ratio of shroud's inside radius to bare cylinder's radius), and shroud orientation with respect to flow were studied. The experiments showed that perforated shrouds with ventilation factors in the range 0.1 to 0.4 and radius ratios in the range 1.1 to 2.1 could enhance the convective heat transfer to bare cylinders up to 50%. The maximum enhancement occurred for a radius ratio of 1.4 and ventilation factors between 0.2 and 0.3. It was found that shroud orientation influenced the heat transfer, with maximum heat transfer generally occurring when the shroud's holes were centered on either side of the stagnation line. However, the hole orientation effect is of second order compared to the influence of ventilation factor and radius ratio.

Multi-scale symbolic transfer entropy analysis of EEG

NASA Astrophysics Data System (ADS)

Yao, Wenpo; Wang, Jun

2017-10-01

From both global and local perspectives, we symbolize two kinds of EEG and analyze their dynamic and asymmetrical information using multi-scale transfer entropy. Multi-scale process with scale factor from 1 to 199 and step size of 2 is applied to EEG of healthy people and epileptic patients, and then the permutation with embedding dimension of 3 and global approach are used to symbolize the sequences. The forward and reverse symbol sequences are taken as the inputs of transfer entropy. Scale factor intervals of permutation and global way are (37, 57) and (65, 85) where the two kinds of EEG have satisfied entropy distinctions. When scale factor is 67, transfer entropy of the healthy and epileptic subjects of permutation, 0.1137 and 0.1028, have biggest difference. And the corresponding values of the global symbolization is 0.0641 and 0.0601 which lies in the scale factor of 165. Research results show that permutation which takes contribution of local information has better distinction and is more effectively applied to our multi-scale transfer entropy analysis of EEG.

System-Level Barriers and Facilitators for Foregoing or Withdrawing Dialysis: A Qualitative Study of Nephrologists in the United States and England.

PubMed

Grubbs, Vanessa; Tuot, Delphine S; Powe, Neil R; O'Donoghue, Donal; Chesla, Catherine A

2017-11-01

Despite a growing body of literature suggesting that dialysis does not confer morbidity or mortality benefits for all patients with chronic kidney failure, the initiation and continuation of dialysis therapy in patients with poor prognosis is commonplace. Our goal was to elicit nephrologists' perspectives on factors that affect decision making regarding end-stage renal disease. Semistructured, individual, qualitative interviews. Participants were purposively sampled based on age, race, sex, geographic location, and practice type. Each was asked about his or her perspectives and experiences related to foregoing and withdrawing dialysis therapy. Interviews were audiotaped, transcribed, and analyzed using narrative and thematic analysis. We conducted 59 semistructured interviews with nephrologists from the United States (n=41) and England (n=18). Most participants were 45 years or younger, men, and white. Average time since completing nephrology training was 14.2±11.6 (SD) years. Identified system-level facilitators and barriers for foregoing and withdrawing dialysis therapy stemmed from national and institutional policies and structural factors, how providers practice medicine (the culture of medicine), and beliefs and behaviors of the public (societal culture). In both countries, the predominant barriers described included lack of training in end-of-life conversations and expectations for aggressive care among non-nephrologists and the general public. Primary differences included financial incentives to dialyze in the United States and widespread outpatient conservative management programs in England. Participants' views may not fully capture those of all American or English nephrologists. Nephrologists in the United States and England identified several system-level factors that both facilitated and interfered with decision making around foregoing and withdrawing dialysis therapy. Efforts to expand facilitators while reducing barriers could lead to care practices more in keeping with patient prognosis. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Improve the Communication, Decrease the Distance: The Investigation into Problematic Communication and Delays in Inter-Hospital Transfer of Rural Trauma Patients

ERIC Educational Resources Information Center

Avtgis, Theodore A.; Polack, E. Phillips; Martin, Matthew M.; Rossi, Daniel

2010-01-01

Time delays in the treatment and transfer of trauma patients is a contributing factor responsible for many fatalities. Time delays are more characteristic of rural trauma systems due to factors such as greater distance, and delays in accident reporting. Efforts to reduce the trauma transfer process have resulted in many changes in protocol and use…

Transfer Factors for Contaminant Uptake by Fruit and Nut Trees

DOE Office of Scientific and Technical Information (OSTI.GOV)

Napier, Bruce A.; Fellows, Robert J.; Minc, Leah D.

Transfer of radionuclides from soils into plants is one of the key mechanisms for long-term contamination of the human food chain. Nearly all computer models that address soil-to-plant uptake of radionuclides use empirically-derived transfer factors to address this process. Essentially all available soil-to-plant transfer factors are based on measurements in annual crops. Because very few measurements are available for tree fruits, samples were taken of alfalfa and oats and the stems, leaves, and fruits and nuts of almond, apple, apricot, carob, fig, grape, nectarine, pecan, pistachio (natural and grafted), and pomegranate, along with local surface soil. The samples were dried,more » ground, weighed, and analyzed for trace constituents through a combination of induction-coupled plasma mass spectrometry and instrumental neutron activation analysis for a wide range of naturally-occurring elements. Analysis results are presented and converted to soil-to-plant transfer factors. These are compared to commonly used and internationally recommended values. Those determined for annual crops are very similar to commonly-used values; those determined for tree fruits show interesting differences. Most macro- and micronutrients are slightly reduced in fruits; non-essential elements are reduced further. These findings may be used in existing computer models and may allow development of tree-fruit-specific transfer models.« less

Factors predicting training transfer in health professionals participating in quality improvement educational interventions.

PubMed

Eid, Ahmed; Quinn, Doris

2017-01-31

Predictors of quality improvement (QI) training transfer are needed. This study aimed to identify these predictors among health professionals who participated in a QI training program held at a large hospital in the United States between 2005 and 2014. It also aimed to determine how these predictive factors facilitated or impeded QI training transfer. Following the Success Case Method, we used a screening survey to identify trainees with high and low levels of training transfer. We then conducted semistructured interviews with a sample of the survey respondents to document how training transfer was achieved and how lack of training transfer could be explained. The survey's response rate was 43%, with a Cronbach alpha of 0.89. We then conducted a thematic analysis of the interview transcripts of 16 physicians. The analysis revealed 3 categories of factors influencing the transfer of QI training: trainee characteristics, training course, and work environment. Relevant trainee characteristics included attitude toward change, motivation, mental processing skills, interpersonal skills, and the personality characteristics curiosity, humility, conscientiousness, resilience, wisdom, and positivity. The training project, team-based learning, and lectures were identified as relevant aspects of the training course. Work culture, work relationships, and resources were subthemes of the work environment category. We identified several QI training transfer predictors in our cohort of physicians. We hypothesize that some of these predictors may be more relevant to QI training transfer. Our results will help organizational leaders select trainees who are most likely to transfer QI training and to ensure that their work environments are conducive to QI training transfer.

Transferring learning from faculty development to the classroom.

PubMed

Rock, Kim Z

2014-12-01

This study’s purpose was to better understand the transfer of learning by uncovering how various factors supported the integration of health information technology knowledge and skills gleaned from the Health Resources and Services Administration–funded faculty development programs into nursing education curricula. Through interviews with 20 participants from four programs, this study confirmed the importance of findings related to faculty, program, and work environment characteristics for supporting successful transfer of learning and substantiates a variety of other transfer-of-learning research. New or seldom discussed supportive individual characteristics were found, including leadership abilities, lifelong learning, ability to recognize limitations, persistence, creativity, and risk taking. The importance of networking, diversity of perspectives, postconference support, and teams in program designs were found to positively influence transfer. The variety of supportive factors and barriers in the participants’ work environments strengthens the assertions that transfer may be context dependent. Findings provided insight for recommendations to improve learning transfer. Copyright 2014, SLACK Incorporated.

Clinical Outcomes among Transferred Children with Ischemic and Hemorrhagic Strokes in the Nationwide Inpatient Sample.

PubMed

Adil, Malik M; Vidal, Gabriel A; Beslow, Lauren A

2016-11-01

Children with ischemic stroke (IS) and hemorrhagic stroke (HS) may require interfacility transfer for higher level of care. We compared the characteristics and clinical outcomes of transferred and nontransferred children with IS and HS. Children aged 1-18 years admitted to hospitals in the United States from 2008 to 2011 with a primary discharge diagnosis of IS and HS were identified from the National Inpatient Sample database by ICD-9 codes. Using logistic regression, we estimated the odds ratios (OR) and 95% confidence intervals (CI) for in-hospital mortality and discharge to nursing facilities (versus discharge home) between transferred and nontransferred patients. Of the 2815 children with IS, 26.7% were transferred. In-hospital mortality and discharge to nursing facilities were not different between transferred and nontransferred children in univariable analysis or in multivariable analysis that adjusted for age, sex, and confounding factors. Of the 6879 children with HS, 27.1% were transferred. Transferred compared to nontransferred children had higher rates of both in-hospital mortality (8% versus 4%, P = .003) and discharge to nursing facilities (25% versus 20%, P = .03). After adjusting for age, sex, and confounding factors, in-hospital mortality (OR 1.5, 95% CI 1.1-2.4, P = .04) remained higher in transferred children, whereas discharge to nursing facilities was not different between the groups. HS but not IS was associated with worse outcomes for children transferred to another hospital compared to children who were not transferred. Additional study is needed to understand what factors may contribute to poorer outcomes among transferred children with HS. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Synergistic effect of electrical and chemical factors on endocytosis in micro-discharge plasma gene transfection

NASA Astrophysics Data System (ADS)

Jinno, M.; Ikeda, Y.; Motomura, H.; Isozaki, Y.; Kido, Y.; Satoh, S.

2017-06-01

We have developed a new micro-discharge plasma (MDP)-based gene transfection method, which transfers genes into cells with high efficiency and low cytotoxicity; however, the mechanism underlying the method is still unknown. Studies revealed that the N-acetylcysteine-mediated inhibition of reactive oxygen species (ROS) activity completely abolished gene transfer. In this study, we used laser-produced plasma to demonstrate that gene transfer does not occur in the absence of electrical factors. Our results show that both electrical and chemical factors are necessary for gene transfer inside cells by microplasma irradiation. This indicates that plasma-mediated gene transfection utilizes the synergy between electrical and chemical factors. The electric field threshold required for transfection was approximately 1 kV m-1 in our MDP system. This indicates that MDP irradiation supplies sufficient concentrations of ROS, and the stimulation intensity of the electric field determines the transfection efficiency in our system. Gene transfer by plasma irradiation depends mainly on endocytosis, which accounts for at least 80% of the transfer, and clathrin-mediated endocytosis is a dominant endocytosis. In plasma-mediated gene transfection, alterations in electrical and chemical factors can independently regulate plasmid DNA adhesion and triggering of endocytosis, respectively. This implies that plasma characteristics can be adjusted according to target cell requirements, and the transfection process can be optimized with minimum damage to cells and maximum efficiency. This may explain how MDP simultaneously achieves high transfection efficiency with minimal cell damage.

Improving NASA's technology transfer process through increased screening and evaluation in the information dissemination program

NASA Technical Reports Server (NTRS)

Laepple, H.

1979-01-01

The current status of NASA's technology transfer system can be improved if the technology transfer process is better understood. This understanding will only be gained if a detailed knowledge about factors generally influencing technology transfer is developed, and particularly those factors affecting technology transfer from government R and D agencies to industry. Secondary utilization of aerospace technology is made more difficult because it depends on a transfer process which crosses established organizational lines of authority and which is outside well understood patterns of technical applications. In the absence of a sound theory about technology transfer and because of the limited capability of government agencies to explore industry's needs, a team approach to screening and evaluation of NASA generated technologies is proposed which calls for NASA, and other organizations of the private and public sectors which influence the transfer of NASA generated technology, to participate in a screening and evaluation process to determine the commercial feasibility of a wide range of technical applications.

Preoperative prognostic value of dynamic contrast-enhanced MRI-derived contrast transfer coefficient and plasma volume in patients with cerebral gliomas.

PubMed

Nguyen, T B; Cron, G O; Mercier, J F; Foottit, C; Torres, C H; Chakraborty, S; Woulfe, J; Jansen, G H; Caudrelier, J M; Sinclair, J; Hogan, M J; Thornhill, R E; Cameron, I G

2015-01-01

The prognostic value of dynamic contrast-enhanced MR imaging-derived plasma volume obtained in tumor and the contrast transfer coefficient has not been well-established in patients with gliomas. We determined whether plasma volume and contrast transfer coefficient in tumor correlated with survival in patients with gliomas in addition to other factors such as age, type of surgery, preoperative Karnofsky score, contrast enhancement, and histopathologic grade. This prospective study included 46 patients with a new pathologically confirmed diagnosis of glioma. The contrast transfer coefficient and plasma volume obtained in tumor maps were calculated directly from the signal-intensity curve without T1 measurements, and values were obtained from multiple small ROIs placed within tumors. Survival curve analysis was performed by dichotomizing patients into groups of high and low contrast transfer coefficient and plasma volume. Univariate analysis was performed by using dynamic contrast-enhanced parameters and clinical factors. Factors that were significant on univariate analysis were entered into multivariate analysis. For all patients with gliomas, survival was worse for groups of patients with high contrast transfer coefficient and plasma volume obtained in tumor (P < .05). In subgroups of high- and low-grade gliomas, survival was worse for groups of patients with high contrast transfer coefficient and plasma volume obtained in tumor (P < .05). Univariate analysis showed that factors associated with lower survival were age older than 50 years, low Karnofsky score, biopsy-only versus resection, marked contrast enhancement versus no/mild enhancement, high contrast transfer coefficient, and high plasma volume obtained in tumor (P < .05). In multivariate analysis, a low Karnofsky score, biopsy versus resection in combination with marked contrast enhancement, and a high contrast transfer coefficient were associated with lower survival rates (P < .05). In patients with glioma, those with a high contrast transfer coefficient have lower survival than those with low parameters. © 2015 by American Journal of Neuroradiology.

The human element in technology transfer

NASA Technical Reports Server (NTRS)

Peake, H. J.

1978-01-01

A transfer model composed of three roles and their linkages was considered. This model and a growing body of experience was analyzed to provide guidance in the human elements of technology transfer. For example, criteria for selection of technology transfer agents was described, and some needed working climate factors were known. These concepts were successfully applied to transfer activities.

Effects of dialysis on the pharmacokinetics of salazosulfapyridine.

PubMed

Inami, Yuko; Yamaji, Ken; Sato, Michiko; Gohda, Tomohito; Io, Hiroaki; Nawata, Masuyuki; Hamada, Chieko; Takasaki, Yoshinari; Tomino, Yasuhiko

2013-02-01

There was no standard or report for the treatment of rheumatoid arthritis (RA) patients on hemodialysis with Salazosulfapyridine (SASP). We examined the pharmacokinetics of SASP and its metabolites in RA patient on hemodialysis. Hemodialysis was started 2 h after administration of SASP at a dose of 250 or 500 mg. Blood samples were took 8 times during the observation period. The concentration of SASP and its metabolites (SP, Ac-SP) in blood sample were measured. There was no difference for the concentration of SASP before and after hemodialysis. Results showed SASP was nondialyzable, but SP and AC-SP were dialyzable. At a dose of 500 mg, AUC0-∞ of SASP and SP were higher than healthy volunteer. Therapy with SASP for hemodialysis RA should be started at a lower dose for adverse event risk.

Studies on heat transfer and pressure drop in turbulent flow of silver - water nanofluids through a circular tube at constant wall heat flux

NASA Astrophysics Data System (ADS)

Iyahraja, S.; Rajadurai, J. Selwin; Rajesh, S.; Pandian, R. Seeni Thangaraj; Kumaran, M. Selva; Selvakumar, G.

2018-07-01

In the present study, performance of convective heat transfer and friction factor of silver-water nanofluids in a horizontal circular pipe under turbulent flow were investigated experimentally under uniform heat flux condition. The volume concentration of silver nanoparticles is varied as 0.01, 0.05 and 0.1%. Heat transfer coefficient and friction factor of nanofluids were measured experimentally by varying the Reynolds number from 3000 to 21,000. It is observed that the addition of even low volume fraction of silver nanoparticles increases both Nusselt number and heat transfer coefficient of the nanofluid significantly. Nusselt number of silver-water nanofluid increases up to 32.6% for 0.1% volume fraction at Reynolds number of 21,000. However, the addition of nanoparticles in the base fluid increases the friction factor slightly. New empirical correlations are also proposed for the estimation of Nusselt number and friction factor of silver-water nanofluid based on the data of present experimental investigation. The proposed correlations of Nusselt number and friction factor show good agreement with their experimental data.

Studies on heat transfer and pressure drop in turbulent flow of silver - water nanofluids through a circular tube at constant wall heat flux

NASA Astrophysics Data System (ADS)

Iyahraja, S.; Rajadurai, J. Selwin; Rajesh, S.; Pandian, R. Seeni Thangaraj; Kumaran, M. Selva; Selvakumar, G.

2018-02-01

In the present study, performance of convective heat transfer and friction factor of silver-water nanofluids in a horizontal circular pipe under turbulent flow were investigated experimentally under uniform heat flux condition. The volume concentration of silver nanoparticles is varied as 0.01, 0.05 and 0.1%. Heat transfer coefficient and friction factor of nanofluids were measured experimentally by varying the Reynolds number from 3000 to 21,000. It is observed that the addition of even low volume fraction of silver nanoparticles increases both Nusselt number and heat transfer coefficient of the nanofluid significantly. Nusselt number of silver-water nanofluid increases up to 32.6% for 0.1% volume fraction at Reynolds number of 21,000. However, the addition of nanoparticles in the base fluid increases the friction factor slightly. New empirical correlations are also proposed for the estimation of Nusselt number and friction factor of silver-water nanofluid based on the data of present experimental investigation. The proposed correlations of Nusselt number and friction factor show good agreement with their experimental data.

Transfer of Learning. Symposium.

ERIC Educational Resources Information Center

2002

This document contains three papers on transfer of training and human resources. "The Effect of Organizational Support, Management Support, and Peer Support on Transfer of Training" (Susan E. Cromwell, Judith A. Kolb) reports on a longitudinal study of work environment factors that affect transfer of training in a university supervisory…

HPTN 068: A Randomized Control Trial of a Conditional Cash Transfer to Reduce HIV Infection in Young Women in South Africa-Study Design and Baseline Results.

PubMed

Pettifor, Audrey; MacPhail, Catherine; Selin, Amanda; Gómez-Olivé, F Xavier; Rosenberg, Molly; Wagner, Ryan G; Mabuza, Wonderful; Hughes, James P; Suchindran, Chirayath; Piwowar-Manning, Estelle; Wang, Jing; Twine, Rhian; Daniel, Tamu; Andrew, Philip; Laeyendecker, Oliver; Agyei, Yaw; Tollman, Stephen; Kahn, Kathleen

2016-09-01

Young women in South Africa are at high risk for HIV infection. Cash transfers offer promise to reduce HIV risk. We present the design and baseline results from HPTN 068, a phase III, individually randomized trial to assess the effect of a conditional cash transfer on HIV acquisition among South African young women. A total of 2533 young women were randomized to receive a monthly cash transfer conditional on school attendance or to a control group. A number of individual-, partner-, household- and school-level factors were associated with HIV and HSV-2 infection. After adjusting for age, all levels were associated with an increased odds of HIV infection with partner-level factors conveying the strongest association (aOR 3.05 95 % CI 1.84-5.06). Interventions like cash transfers that address structural factors such as schooling and poverty have the potential to reduce HIV risk in young women in South Africa.

Stakeholders' perceptions of transferability criteria for health promotion interventions: a case study.

PubMed

Trompette, Justine; Kivits, Joëlle; Minary, Laetitia; Cambon, Linda; Alla, François

2014-11-04

The effects of health promotion interventions are the result not only of the interventions themselves, but also of the contexts in which they unfold. The objective of this study was to analyze, through stakeholders' discourse, the characteristics of an intervention that can influence its outcomes. This case study was based on semi-structured interviews with health promotion stakeholders involved in a regional program (PRALIMAP). General hypotheses on transferability and on how the intervention is presumed to produce its effects were used to construct an interview guide. Interviews were analyzed using thematic coding. Twenty-three stakeholders were interviewed. Results showed stakeholders made few references to population and environment characteristics. Three themes emerged as significant for the stakeholders: implementation modalities and methodology, modalities used to mobilize actors; and transferability-promoting factors and barriers. Our work contributes to a better understanding not only of transferability factors, but also of stakeholders' perceptions of them, which are just as important, because those perceptions themselves are a factor in mobilization of actors, implementation, and transferability.

Training transfer: a systematic review of the impact of inner setting factors.

PubMed

Jackson, Carrie B; Brabson, Laurel A; Quetsch, Lauren B; Herschell, Amy D

2018-06-19

Consistent with Baldwin and Ford's model (Pers Psychol 41(1):63-105, 1988), training transfer is defined as the generalization of learning from a training to everyday practice in the workplace. The purpose of this review was to examine the influence of work-environment factors, one component of the model hypothesized to influence training transfer within behavioral health. An electronic literature search guided by the Consolidated Framework for Implementation Research's inner setting domain was conducted was conducted on Medline OVID, Medline EMBASE, and PsycINFO databases. Of 9184 unique articles, 169 full-text versions of articles were screened for eligibility, yielding 26 articles meeting inclusion criteria. Results from the 26 studies revealed that overall, having more positive networks and communication, culture, implementation climate, and readiness for implementation can facilitate training transfer. Although few studies have examined the impact of inner setting factors on training transfer, these results suggest organizational context is important to consider with training efforts. These findings have important implications for individuals in the broader health professions educational field.

Experimental evaluation of a mathematical model for predicting transfer efficiency of a high volume-low pressure air spray gun.

PubMed

Tan, Y M; Flynn, M R

2000-10-01

The transfer efficiency of a spray-painting gun is defined as the amount of coating applied to the workpiece divided by the amount sprayed. Characterizing this transfer process allows for accurate estimation of the overspray generation rate, which is important for determining a spray painter's exposure to airborne contaminants. This study presents an experimental evaluation of a mathematical model for predicting the transfer efficiency of a high volume-low pressure spray gun. The effects of gun-to-surface distance and nozzle pressure on the agreement between the transfer efficiency measurement and prediction were examined. Wind tunnel studies and non-volatile vacuum pump oil in place of commercial paint were used to determine transfer efficiency at nine gun-to-surface distances and four nozzle pressure levels. The mathematical model successfully predicts transfer efficiency within the uncertainty limits. The least squares regression between measured and predicted transfer efficiency has a slope of 0.83 and an intercept of 0.12 (R2 = 0.98). Two correction factors were determined to improve the mathematical model. At higher nozzle pressure settings, 6.5 psig and 5.5 psig, the correction factor is a function of both gun-to-surface distance and nozzle pressure level. At lower nozzle pressures, 4 psig and 2.75 psig, gun-to-surface distance slightly influences the correction factor, while nozzle pressure has no discernible effect.

University Technology Transfer Factors as Predictors of Entrepreneurial Orientation

ERIC Educational Resources Information Center

Kirkman, Dorothy M.

2011-01-01

University technology transfer is a collaborative effort between academia and industry involving knowledge sharing and learning. Working closely with their university partners affords biotechnology firms the opportunity to successfully develop licensed inventions and gain access to novel scientific and technological discoveries. These factors may…

Cash transfer and microfinance interventions for tuberculosis control: review of the impact evidence and policy implications.

PubMed

Boccia, D; Hargreaves, J; Lönnroth, K; Jaramillo, E; Weiss, J; Uplekar, M; Porter, J D H; Evans, C A

2011-06-01

To quantify the impact of cash transfer and microfinance interventions on a selected list of tuberculosis (TB) risk factors and assess their potential role in supporting TB control. Published and unpublished references identified from clinical and social electronic databases, grey literature and web sites. Eligible interventions had to be conducted in middle- or low-income countries and document an impact evaluation on any of the following outcomes: 1) TB or other respiratory infections; 2) household socio-economic position; and 3) factors mediating the association between low household socio-economic position and TB, including inadequate health-seeking behaviours, food insecurity and biological TB risk factors such as human immunodeficiency virus (HIV) and adult malnutrition. Interventions targeting special populations were excluded. Fifteen cash transfer schemes (four unconditional and 11 conditional) and seven microfinance programmes met the eligibility criteria. No intervention addressed TB or any other respiratory infection. Of 11 cash transfer and four microfinance interventions, respectively seven and four reported a positive impact on indicators of economic well-being. A positive impact on household food security was documented in respectively eight of nine and three of five cash transfer and microfinance interventions. Improved health care access was documented respectively in 10 of 12 cash transfer and four of five microfinance interventions. The only intervention evaluating impact on HIV incidence was a microfinance project that found no effect. No cash transfer or microfinance interventions had an impact on adult malnutrition. Cash transfer and microfinance interventions can positively impact TB risk factors. Evaluation studies are urgently needed to assess the impact of these social protection interventions on actual TB indicators.

Societal and economic valuation of technology-transfer deals

NASA Astrophysics Data System (ADS)

Holmes, Joseph S., Jr.

2009-09-01

The industrial adoption of concepts such as open innovation brings new legitimacy to activities technology-transfer professionals have conducted for over 20 years. This movement highlights the need for an increased understanding of the valuation of intellectual property (IP) and technology-transfer deals. Valuation, though a centerpiece of corporate finance, is more challenging when applied to the inherent uncertainty surrounding innovation. Technology-transfer professionals are often overwhelmed by the complexity and data requirements of valuation techniques and skeptical of their applicability to and utility for technology transfer. The market longs for an approach which bridges the gap between valuation fundamentals and technology-transfer realities. This paper presents the foundations of a simple, flexible, precise/accurate, and useful framework for considering the valuation of technology-transfer deals. The approach is predicated on a 12-factor model—a 3×4 value matrix predicated on categories of economic, societal, and strategic value. Each of these three categories consists of three core subcategories followed by a fourth "other" category to facilitate inevitable special considerations. This 12-factor value matrix provides a framework for harvesting data during deals and for the application of best-of-breed valuation techniques which can be employed on a per-factor basis. Future work will include framework implementation within a database platform.

Monochorionic triplets after single embryo transfer.

PubMed

Rísquez, Francisco; Gil, Mónica; D'Ommar, Gustavo; Poo, María; Sosa, Anna; Piras, Marta

2004-10-01

A 40-year-old patient underwent intracytoplasmic sperm injection and assisted hatching, and a single embryo was transferred. Ultrasonography demonstrated a single gestational sac containing monochorionic tri-amniotic pregnancy. Several factors that have been implicated in the aetiology of monozygotic triple pregnancies after IVF appear to be present in this case. To avoid multiple pregnancies after IVF, it is time to have definite predictive factors for the occurrence of monozygotic multiple pregnancies as well as transferring only a single embryo.

Properties of an R Factor from Pseudomonas aeruginosa

PubMed Central

Datta, Naomi; Hedges, R. W.; Shaw, Elizabeth J.; Sykes, R. B.; Richmond, M. H.

1971-01-01

An R factor from Pseudomonas aeruginosa, which confers resistance to penicillins, kanamycin, and tetracycline, was studied in Escherichia coli K-12. The R factor could coexist with F-like or I-like plasmids and therefore constituted a novel compatibility group. The R factor was transferable from E. coli to bacterial genera outside the Enterobacteriaceae (Pseudomonas and members of the Rhizobiaceae) to which transfer of F-like and I-like plasmids could not be demonstrated. PMID:4945193

Energy transfer between a nanosystem and its host fluid: A multiscale factorization approach

NASA Astrophysics Data System (ADS)

Sereda, Yuriy V.; Espinosa-Duran, John M.; Ortoleva, Peter J.

2014-02-01

Energy transfer between a macromolecule or supramolecular assembly and a host medium is considered from the perspective of Newton's equations and Lie-Trotter factorization. The development starts by demonstrating that the energy of the molecule evolves slowly relative to the time scale of atomic collisions-vibrations. The energy is envisioned to be a coarse-grained variable that coevolves with the rapidly fluctuating atomistic degrees of freedom. Lie-Trotter factorization is shown to be a natural framework for expressing this coevolution. A mathematical formalism and workflow for efficient multiscale simulation of energy transfer is presented. Lactoferrin and human papilloma virus capsid-like structure are used for validation.

Charge form factor of the neutron at low momentum transfer from the 2H-->(e-->,e'n)1H reaction.

PubMed

Geis, E; Kohl, M; Ziskin, V; Akdogan, T; Arenhövel, H; Alarcon, R; Bertozzi, W; Booth, E; Botto, T; Calarco, J; Clasie, B; Crawford, C B; DeGrush, A; Donnelly, T W; Dow, K; Farkhondeh, M; Fatemi, R; Filoti, O; Franklin, W; Gao, H; Gilad, S; Hasell, D; Karpius, P; Kolster, H; Lee, T; Maschinot, A; Matthews, J; McIlhany, K; Meitanis, N; Milner, R G; Rapaport, J; Redwine, R P; Seely, J; Shinozaki, A; Sirca, S; Sindile, A; Six, E; Smith, T; Steadman, M; Tonguc, B; Tschalaer, C; Tsentalovich, E; Turchinetz, W; Xiao, Y; Xu, W; Zhang, C; Zhou, Z; Zwart, T

2008-07-25

We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio GEn/GMn was extracted from the beam-target vector asymmetry AedV at four-momentum transfers Q2=0.14, 0.20, 0.29, and 0.42 (GeV/c)2.

Studies on uptake and retention of trace elements by medicinal plants in the environs of Hassan of South India

NASA Astrophysics Data System (ADS)

Jagadeesha, B. G.; Narayana, Y.; Sudarshan, M.; Banerjee, Shamayita

2018-03-01

The transfer factors of trace elements from soil to medicinal plants were determined in the region of Hassan district of south India. The trace element concentration was determined using the Energy Dispersive X-ray Fluorescence (ED-XRF) spectrometer. The transfer factors were found in the order Rb > Sr > Ca > K > Zn > Cu > Mn. The transfer factors were found to be high, for most of the plants. The concentration of Rb and Sr was found to be high in medicinal plants, which can be attributed to the mineralogy of the region and plant morphology.

Numerical simulation of turbulent flow and heat transfer though sinusoidal ducts

NASA Astrophysics Data System (ADS)

Abroshan, Hamid

2018-02-01

Turbulent forced convection heat transfer in corrugated plate surfaces was studied by means of CFD. Flow through corrugated plates, which are sets of sinusoidal ducts, was analyzed for different inlet flow angles (0° to 50°), aspect ratios (0.1 to 10), Reynolds numbers (2000 to 40,000) and Prantdel numbers (0.7 to 5). Heat transfer is affected significantly by variation of aspect ratio. A maximum heat transfer coefficient is observed at a particular aspect ratio although the aspect ratio has a minor effect on friction factor. Enlarging inlet flow angle also leads to a higher heat transfer coefficient and pressure loss in aspect ratios close to unity. Dependency of Nusselt and friction factor on the angle and aspect ratio was interpreted by means of appearance of secondary motions and coexistence of laminar and turbulent flow in a cross section. Comparing the results with experimental data shows a maximum 12.8% difference. By evaluating the results, some correlations were proposed to calculate Nusselt number and friction factor for entrance and fully developed regions. A corrugated plate with an aspect ratio equal to 1.125 and an inlet flow angle equal to 50° gives the best heat transfer and pressure drop characteristics.

Modification of an impulse-factoring orbital transfer technique to account for orbit determination and maneuver execution errors

NASA Technical Reports Server (NTRS)

Kibler, J. F.; Green, R. N.; Young, G. R.; Kelly, M. G.

1974-01-01

A method has previously been developed to satisfy terminal rendezvous and intermediate timing constraints for planetary missions involving orbital operations. The method uses impulse factoring in which a two-impulse transfer is divided into three or four impulses which add one or two intermediate orbits. The periods of the intermediate orbits and the number of revolutions in each orbit are varied to satisfy timing constraints. Techniques are developed to retarget the orbital transfer in the presence of orbit-determination and maneuver-execution errors. Sample results indicate that the nominal transfer can be retargeted with little change in either the magnitude (Delta V) or location of the individual impulses. Additonally, the total Delta V required for the retargeted transfer is little different from that required for the nominal transfer. A digital computer program developed to implement the techniques is described.

Information Transfer Analysis of Spontaneous Low-frequency Fluctuations in Cerebral Hemodynamics and Cardiovascular Dynamics

NASA Astrophysics Data System (ADS)

Katura, Takusige; Tanaka, Naoki; Obata, Akiko; Sato, Hiroki; Maki, Atsushi

2005-08-01

In this study, from the information-theoretic viewpoint, we analyzed the interrelation between the spontaneous low-frequency fluctuations around 0.1Hz in the hemoglobin concentration in the cerebral cortex, mean arterial blood pressure and the heart rate. For this analysis, as measures of information transfer, we used transfer entropy (TE) proposed for two-factor systems by Schreiber and intrinsic transfer entropy (ITE) introduced for further analysis of three-factor systems by extending the original TE. In our analysis, information transfer analysis based on both TE and ITE suggests the systemic cardiovascular fluctuations alone cannot account for the cerebrovascular fluctuations, that is, the regulation of the regional cerebral energetic metabolism is important as a candidate of its generation mechanism Such an information transfer analysis seems useful to reveal the interrelation between the elements regulated each other in a complex manner.

TRANSFER OF DRUG RESISTANCE BETWEEN ENTERIC BACTERIA INDUCED IN THE MOUSE INTESTINE

PubMed Central

Kasuya, Morimasa

1964-01-01

Kasuya, Morimasa (Nagoya University School of Medicine, Nagoya, Japan). Transfer of drug resistance between enteric bacteria induced in the mouse intestine. J. Bacteriol. 88:322–328. 1964.—Transfer of multiple drug resistance in the intestines of germ-free and conventional mice was studied with strains of Shigella, Escherichia, and Klebsiella. The transfer experiment was carried out under antibiotic-free conditions to eliminate the production of drug-resistant bacteria by antibiotics. All resistance factors (chloramphenicol, streptomycin, tetracycline, and sulfathiazole) were transferred with ease in the intestinal tracts of mice, when donors and recipients multiplied freely, and acquired resistance was further transferred to other sensitive enteric bacteria in the intestinal tract. Bacteria to which resistance factors were transferred showed, in most of the experiments, exactly the same level and pattern of resistance as the donors. Based on the above, a hypothesis that the same process may possibly occur in the human intestine is presented. PMID:14203347

Sidestream superoxygenation for wastewater treatment: Oxygen transfer in clean water and mixed liquor.

PubMed

Barreto, Carlos M; Ochoa, Ivania M; Garcia, Hector A; Hooijmans, Christine M; Livingston, Dennis; Herrera, Aridai; Brdjanovic, Damir

2018-08-01

The performance of a pilot-scale superoxygenation system was evaluated in clean water and mixed liquor. A mass balance was applied over the pilot-scale system to determine the overall oxygen mass transfer rate coefficient (K L a, h -1 ), the standard oxygen transfer rate (SOTR, kg O 2 d -1 ), and the standard oxygen transfer efficiency (SOTE, %). Additionally, the alpha factor (α) was determined at a mixed liquor suspend solids (MLSS) concentration of approximately 5 g L -1 . SOTEs of nearly 100% were obtained in clean water and mixed liquor. The results showed that at higher oxygen flowrates, higher transfer rates could be achieved; this however, at expenses of the transfer efficiency. As expected, lower transfer efficiencies were observed in mixed liquor compared to clean water. Alpha factors varied between 0.6 and 1.0. However, values of approximately 1.0 can be obtained in all cases by fine tuning the oxygen flowrate delivered to the system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of an Accident Reproduction Simulator System Using a Hemodialysis Extracorporeal Circulation System

PubMed Central

Nishite, Yoshiaki; Takesawa, Shingo

2016-01-01

Background: Accidents that occur during dialysis treatment are notified to the medical staff via alarms raised by the dialysis apparatus. Similar to such real accidents, apparatus activation or accidents can be reproduced by simulating a treatment situation. An alarm that corresponds to such accidents can be utilized in the simulation model. Objectives: The aim of this study was to create an extracorporeal circulation system (hereinafter, the circulation system) for dialysis machines so that it sets off five types of alarms for: 1) decreased arterial pressure, 2) increased arterial pressure, 3) decreased venous pressure, 4) increased venous pressure, and 5) blood leakage, according to the five types of accidents chosen based on their frequency of occurrence and the degree of severity. Materials and Methods: In order to verify the alarm from the dialysis apparatus connected to the circulation system and the accident corresponding to it, an evaluation of the alarm for its reproducibility of an accident was performed under normal treatment circumstances. The method involved testing whether the dialysis apparatus raised the desired alarm from the moment of control of the circulation system, and measuring the time it took until the desired alarm was activated. This was tested on five main models from four dialyzer manufacturers that are currently used in Japan. Results: The results of the tests demonstrated successful activation of the alarms by the dialysis apparatus, which were appropriate for each of the five types of accidents. The time between the control of the circulatory system to the alarm signal was as follows, 1) venous pressure lower limit alarm: 7 seconds; 2) venous pressure lower limit: 8 seconds; 3) venous pressure upper limit: 7 seconds; 4) venous pressure lower limit alarm: 2 seconds; and 5) blood leakage alarm: 19 seconds. All alarms were set off in under 20 seconds. Conclusions: Thus, we can conclude that a simulator system using an extracorporeal circulation system can be set to different models of dialyzers, and that the reproduced treatment scenarios can be used for simulation training. PMID:26981503

Calmodulin kinase II and protein kinase C mediate the effect of increased intracellular calcium to augment late sodium current in rabbit ventricular myocytes.

PubMed

Ma, Jihua; Luo, Antao; Wu, Lin; Wan, Wei; Zhang, Peihua; Ren, Zhiqiang; Zhang, Shuo; Qian, Chunping; Shryock, John C; Belardinelli, Luiz

2012-04-15

An increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) augments late sodium current (I(Na.L)) in cardiomyocytes. This study tests the hypothesis that both Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) and protein kinase C (PKC) mediate the effect of increased [Ca(2+)](i) to increase I(Na.L). Whole cell and open cell-attached patch clamp techniques were used to record I(Na.L) in rabbit ventricular myocytes dialyzed with solutions containing various concentrations of [Ca(2+)](i). Dialysis of cells with [Ca(2+)](i) from 0.1 to 0.3, 0.6, and 1.0 μM increased I(Na.L) in a concentration-dependent manner from 0.221 ± 0.038 to 0.554 ± 0.045 pA/pF (n = 10, P < 0.01) and was associated with an increase in mean Na(+) channel open probability and prolongation of channel mean open-time (n = 7, P < 0.01). In the presence of 0.6 μM [Ca(2+)](i), KN-93 (10 μM) and bisindolylmaleimide (BIM, 2 μM) decreased I(Na.L) by 45.2 and 54.8%, respectively. The effects of KN-93 and autocamtide-2-related inhibitory peptide II (2 μM) were not different. A combination of KN-93 and BIM completely reversed the increase in I(Na.L) as well as the Ca(2+)-induced changes in Na(+) channel mean open probability and mean open-time induced by 0.6 μM [Ca(2+)](i). Phorbol myristoyl acetate increased I(Na.L) in myocytes dialyzed with 0.1 μM [Ca(2+)](i); the effect was abolished by Gö-6976. In summary, both CaMKII and PKC are involved in [Ca(2+)](i)-mediated augmentation of I(Na.L) in ventricular myocytes. Inhibition of CaMKII and/or PKC pathways may be a therapeutic target to reduce myocardial dysfunction and cardiac arrhythmias caused by calcium overload.

Extracorporeal treatment for valproic acid poisoning: systematic review and recommendations from the EXTRIP workgroup.

PubMed

Ghannoum, Marc; Laliberté, Martin; Nolin, Thomas D; MacTier, Robert; Lavergne, Valery; Hoffman, Robert S; Gosselin, Sophie

2015-06-01

The EXtracorporeal TReatments In Poisoning (EXTRIP) workgroup presents its systematic review and clinical recommendations on the use of extracorporeal treatment (ECTR) in valproic acid (VPA) poisoning. The lead authors reviewed all of the articles from a systematic literature search, extracted the data, summarized the key findings, and proposed structured voting statements following a predetermined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements and the RAND/UCLA Appropriateness Method was used to quantify disagreement. Anonymous votes were compiled, returned, and discussed in person. A second vote was conducted to determine the final workgroup recommendations. The latest literature search conducted in November 2014 retrieved a total of 79 articles for final qualitative analysis, including one observational study, one uncontrolled cohort study with aggregate analysis, 70 case reports and case series, and 7 pharmacokinetic studies, yielding a very low quality of evidence for all recommendations. Clinical data were reported for 82 overdose patients while pharmaco/toxicokinetic grading was performed in 55 patients. The workgroup concluded that VPA is moderately dialyzable (level of evidence = B) and made the following recommendations: ECTR is recommended in severe VPA poisoning (1D); recommendations for ECTR include a VPA concentration > 1300 mg/L (9000 μmol/L)(1D), the presence of cerebral edema (1D) or shock (1D); suggestions for ECTR include a VPA concentration > 900 mg/L (6250 μmol/L)(2D), coma or respiratory depression requiring mechanical ventilation (2D), acute hyperammonemia (2D), or pH ≤ 7.10 (2D). Cessation of ECTR is indicated when clinical improvement is apparent (1D) or the serum VPA concentration is between 50 and 100 mg/L (350-700 μmol/L)(2D). Intermittent hemodialysis is the preferred ECTR in VPA poisoning (1D). If hemodialysis is not available, then intermittent hemoperfusion (1D) or continuous renal replacement therapy (2D) is an acceptable alternative. VPA is moderately dialyzable in the setting of overdose. ECTR is indicated for VPA poisoning if at least one of the above criteria is present. Intermittent hemodialysis is the preferred ECTR modality in VPA poisoning.

Functional genomic analysis identifies indoxyl sulfate as a major, poorly dialyzable uremic toxin in end-stage renal disease.

PubMed

Jhawar, Sachin; Singh, Prabhjot; Torres, Daniel; Ramirez-Valle, Francisco; Kassem, Hania; Banerjee, Trina; Dolgalev, Igor; Heguy, Adriana; Zavadil, Jiri; Lowenstein, Jerome

2015-01-01

Chronic renal failure is characterized by progressive renal scarring and accelerated arteriosclerotic cardiovascular disease despite what is considered to be adequate hemodialysis or peritoneal dialysis. In rodents with reduced renal mass, renal scarring has been attributed to poorly filtered, small protein-bound molecules. The best studied of these is indoxyl sulfate (IS). We have attempted to establish whether there are uremic toxins that are not effectively removed by hemodialysis. We examined plasma from patients undergoing hemodialysis, employing global gene expression in normal human renal cortical cells incubated in pre- and post- dialysis plasma as a reporter system. Responses in cells incubated with pre- and post-dialysis uremic plasma (n = 10) were compared with responses elicited by plasma from control subjects (n = 5). The effects of adding IS to control plasma and of adding probenecid to uremic plasma were examined. Plasma concentrations of IS were measured by HPLC (high pressure liquid chromatography). Gene expression in our reporter system revealed dysregulation of 1912 genes in cells incubated with pre-dialysis uremic plasma. In cells incubated in post-dialysis plasma, the expression of 537 of those genes returned to baseline but the majority of them (1375) remained dysregulated. IS concentration was markedly elevated in pre- and post-dialysis plasma. Addition of IS to control plasma simulated more than 80% of the effects of uremic plasma on gene expression; the addition of probenecid, an organic anion transport (OAT) inhibitor, to uremic plasma reversed the changes in gene expression. These findings provide evidence that hemodialysis fails to effectively clear one or more solutes that effect gene expression, in our reporter system, from the plasma of patients with uremia. The finding that gene dysregulation was simulated by the addition of IS to control plasma and inhibited by addition of an OAT inhibitor to uremic plasma identifies IS as a major, poorly dialyzable, uremic toxin. The signaling pathways initiated by IS and possibly other solutes not effectively removed by dialysis may participate in the pathogenesis of renal scarring and uremic vasculopathy.

Factors Affecting the Transfer of Basic Combat Skills Training in the Air Force

DTIC Science & Technology

2006-03-01

Kaiser - Meyer - Olkin Measure of Sampling Adequacy (KMO) and Bartlett’s test of Sphericity. The items reported a KMO=.87 and χ2 = 5,158.57, p < .01...Results Factor Analysis Table E1 Kaiser - Meyer - Olkin (KMO) and Bartlett’s Test of Sphericity for Perceived Training Transfer and Transfer Enhancing...Activities KMO Χ2 df Sig. Kaiser - Meyer - Olkin Measure of Sampling Adequacy .87 Bartletts Test of Sphericity 5,158.57 66 .000 100

Polarization transfer observables in elastic electron-proton scattering at Q 2 = 2.5 , 5.2, 6.8, and 8.5   GeV 2

DOE PAGES

Puckett, Andrew J. R.; Brash, E. J.; Jones, M. K.; ...

2017-11-06

In this paper, interest in the behavior of nucleon electromagnetic form factors at large momentum transfers has steadily increased since the discovery, using polarization observables, of the rapid decrease of the ratio G p E/G p M of the proton's electric and magnetic form factors for momentum transfers Q 2 ≳ 1 GeV 2, in strong disagreement with previous extractions of this ratio using the traditional Rosenbluth separation technique.

Polarization transfer observables in elastic electron-proton scattering at Q 2 = 2.5 , 5.2, 6.8, and 8.5   GeV 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puckett, Andrew J. R.; Brash, E. J.; Jones, M. K.

In this paper, interest in the behavior of nucleon electromagnetic form factors at large momentum transfers has steadily increased since the discovery, using polarization observables, of the rapid decrease of the ratio G p E/G p M of the proton's electric and magnetic form factors for momentum transfers Q 2 ≳ 1 GeV 2, in strong disagreement with previous extractions of this ratio using the traditional Rosenbluth separation technique.

Factors Contributing to the Upward Transfer of Baccalaureate Aspirants Beginning at Community Colleges

ERIC Educational Resources Information Center

Wang, Xueli

2012-01-01

This study examined factors associated with the upward transfer of baccalaureate aspirants beginning at community colleges. Based on data from the National Education Longitudinal Study of 1988 and the Postsecondary Education Transcript Study, a sequential logistic regression analysis was conducted to predict bachelor's degree-seeking community…

Goals, Family, and Community: What Drives Tribal College Transfer Student Success

ERIC Educational Resources Information Center

Makomenaw, Matthew

2014-01-01

This article examines success factors for American Indian tribal college students who transfer to 4-year predominantly White institutions. The study examined the experiences of 8 tribal college transfer students to Midwest universities. Using an indigenous methodology, 3 themes were found to help American Indian tribal college transfer students…

The Factors That Influence Transfer of Training and Its Effect on Organizational Citizenship Behaviour

ERIC Educational Resources Information Center

Nik Nazli, Nik Nadian Nisa; Sheikh Khairudin, Sheikh Muhamad Hizam

2018-01-01

Purpose: This paper aims to identify the relationship between organizational learning culture, psychological contract breach, work engagement, training simulation and transfer of training, to examine the effect of transfer of training on organizational citizenship behaviour and to determine the mediating effect of transfer of training on the…

Linking Positive Affect and Motivation to Transfer within Training: A Multilevel Study

ERIC Educational Resources Information Center

Paulsen, Hilko Frederik Klaas; Kauffeld, Simone

2017-01-01

Motivation to transfer is a critical element for successful training transfer. Whereas recent research has shown that training-related factors such as training design are related to motivation to transfer, participants' affective experiences have been neglected. Based on the broaden-and-build theory of positive emotions, we conducted a multilevel…

Prediction of alpha factor values for fine pore aeration systems.

PubMed

Gillot, S; Héduit, A

2008-01-01

The objective of this work was to analyse the impact of different geometric and operating parameters on the alpha factor value for fine bubble aeration systems equipped with EPDM membrane diffusers. Measurements have been performed on nitrifying plants operating under extended aeration and treating mainly domestic wastewater. Measurements performed on 14 nitrifying plants showed that, for domestic wastewater treatment under very low F/M ratios, the alpha factor is comprised between 0.44 and 0.98. A new composite variable (the Equivalent Contact Time, ECT) has been defined and makes it possible for a given aeration tank, knowing the MCRT, the clean water oxygen transfer coefficient and the supplied air flow rate, to predict the alpha factor value. ECT combines the effect on mass transfer of all generally accepted factors affecting oxygen transfer performances (air flow rate, diffuser submergence, horizontal flow). (c) IWA Publishing 2008.

An evaluation of the wind chill factor: its development and applicability.

PubMed

Bluestein, M

1998-04-01

The wind chill factor has become a standard meteorologic term in cold climates. Meteorologic charts provide wind chill temperatures meant to represent the hypothetical air temperature that would, under conditions of no wind, effect the same heat loss from unclothed human skin as does the actual combination of air temperature and wind velocity. As this wind chill factor has social and economic significance, an investigation was conducted on the development of this factor and its applicability based on modern heat transfer principles. The currently used wind chill factor was found to be based on a primitive study conducted by the U.S. Antarctic Service over 50 years ago. The resultant equation for the wind chill temperature assumes an unrealistic constant skin temperature and utilizes heat transfer coefficients that differ markedly from those obtained from equations of modern convective heat transfer methods. The combined effect of these two factors is to overestimate the effect of a given wind velocity and to predict a wind chill temperature that is too low.

Oxidative stress in uremia: nature, mechanisms, and potential consequences.

PubMed

Vaziri, Nosratola D

2004-09-01

Oxidative stress has emerged as a constant feature of chronic renal failure (CRF). The presence of oxidative stress in CRF is evidenced by an overabundance of lipid, carbohydrate, and protein oxidation products in the plasma and tissues of uremic patients and animals. We recently have shown that oxidative stress in CRF animals is associated with and, in part, owing to up-regulation of superoxide-producing enzyme, nicotinamide-adenine dinucleotide phosphate (NAD(P)H) oxidase, and down-regulation of superoxide dismutase (SOD). The functional significance of these findings was confirmed by favorable response to administration of the cell-permeable SOD-mimetic agent, tempol, in CRF rats. Oxidative stress in CRF plays an important role in the pathogenesis of the associated hypertension (oxidation of NO and arachidonic acid and vascular remodeling), cardiovascular disease (oxidation of lipoproteins, atherogenesis), neurologic disorders (nitration of brain proteins, oxidation of myelin), anemia (reduction of erythrocyte lifespan), inflammation (nuclear factor kappa B activation), fibrosis, apoptosis, and accelerated aging. The CRF-induced oxidative stress is aggravated by diabetes, uncontrolled hypertension, and autoimmune diseases, which independently increase production of reactive oxygen intermediates, and frequently are associated with CRF. In addition, dialysis treatment (blood interaction with dialyzer membrane and dialysate impurities), acute and chronic infections (blood access infection, hepatitis, and so forth), and excessive parenteral iron administration intensify CRF-associated oxidative stress and its adverse consequences in patients with end-stage renal disease. The problem is compounded by limited intake of fresh fruits and vegetables (K(+) restriction), which contain numerous natural phytochemicals and antioxidant vitamins.

The ultrasonic-enhanced factor of mass-transfer coefficient in the supercritical carbon dioxide extraction

NASA Astrophysics Data System (ADS)

Luo, Benyi; Lu, Yigang

2008-10-01

Based on several hypotheses about the process of supercritical carbon dioxide extraction, the onflow around the solute granule is figured out by the Navier-Stocks equation. In combination with the Higbie’s solute infiltration model, the link between the mass-transfer coefficient and the velocity of flow is found. The mass-transfer coefficient with the ultrasonical effect is compared with that without the ultrasonical effect, and then a new parameter named the ultrasonic-enhanced factor of mass-transfer coefficient is brought forward, which describes the mathematical model of the supercritical carbon dioxide extraction process enhanced by ultrasonic. The model gives out the relationships among the ultrasonical power, the ultrasonical frequency, the radius of solute granule and the ultrasonic-enhanced factor of mass-transfer coefficient. The results calculated by this model fit well with the experimental data, including the extraction of Coix Lacryma-jobi Seed Oil (CLSO) and Coix Lacryma-jobi Seed Ester (CLSE) from coix seeds and the extraction of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) from the alga by means of the ultrasonic-enhanced supercritical carbon dioxide extraction (USFE) and the supercritical carbon dioxide extraction (SFE) respectively. This proves the rationality of the ultrasonic-enhanced factor model. The model provides a theoretical basis for the application of ultrasonic-enhanced supercritical fluid extraction technique.

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

NASA Astrophysics Data System (ADS)

Cadena, M. S. Reyes; Chapul, L. Sánchez; Pérez, Javiér; García, M. N. Jiménez; López, M. A. Jiménez; Espíndola, M. E. Sánchez; Perez, R. Paniagua; Hernández, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodríguez

2008-08-01

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-β) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

High-surface-area architectures for improved charge transfer kinetics at the dark electrode in dye-sensitized solar cells.

PubMed

Hoffeditz, William L; Katz, Michael J; Deria, Pravas; Martinson, Alex B F; Pellin, Michael J; Farha, Omar K; Hupp, Joseph T

2014-06-11

Dye-sensitized solar cell (DSC) redox shuttles other than triiodide/iodide have exhibited significantly higher charge transfer resistances at the dark electrode. This often results in poor fill factor, a severe detriment to device performance. Rather than moving to dark electrodes of untested materials that may have higher catalytic activity for specific shuttles, the surface area of platinum dark electrodes could be increased, improving the catalytic activity by simply presenting more catalyst to the shuttle solution. A new copper-based redox shuttle that experiences extremely high charge-transfer resistance at conventional Pt dark electrodes yields cells having fill-factors of less than 0.3. By replacing the standard Pt dark electrode with an inverse opal Pt electrode fabricated via atomic layer deposition, the dark electrode surface area is boosted by ca. 50-fold. The resulting increase in interfacial electron transfer rate (decrease in charge-transfer resistance) nearly doubles the fill factor and therefore the overall energy conversion efficiency, illustrating the utility of this high-area electrode for DSCs.

Verification of radionuclide transfer factors to domestic-animal food products, using indigenous elements and with emphasis on iodine.

PubMed

Sheppard, S C; Long, J M; Sanipelli, B

2010-11-01

Recent reviews have established benchmark values for transfer factors that describe radionuclide transfer from plants to animal food product such as milk, eggs and meat. They also illustrate the paucity of data for some elements and some food products. The present study quantified transfer data using indigenous elements measured in dairy, poultry and other livestock farms in Canada. Up to 62 elements are reported, with particular emphasis on iodine (I) because of the need to accurately assess the behaviour of (129)I from disposal of nuclear fuel waste. There was remarkable agreement with the literature values, and for many elements the present study involved many more observations than were previously available. Perhaps the most important observation was that product/substrate concentration ratios (CR) were quite consistent across species, whereas the traditional fractional transfer factors (TF, units of d kg(-1) or d L(-1)) necessarily vary with body mass (feed intake). This suggests that for long-term assessments, it may be advisable to change the models to use CR rather than TF.

[Analysis of the clinical course of disease and subsequent dialysis therapy in a group of patients with rheumatoid arthritis and end-stage renal disease].

PubMed

Majdan, Maria; Stepniak, Cezary; Piotrowicz, Sebastian; Broniek, Karina; Blajer, Beata; Bednarek-Skublewska, Anna

2005-04-01

The chronic nephropathy is often present in pts with rheumatoid arthritis (RA). In the study the authors retrospectively analyzed the clinical course of the disease and outcomes of subsequent dialysotherapy in a group of pts with RA and end-stage renal disease ESRD. During last 5 years ESRD connected with RA was found in 10 (8 F, 2 M) pts out of 325 chronically dialyzed pts (peritoneal dialysis and hemodialysis) representing 3,1% of pts. The mean age at the initiation of dialysotherapy in these pts was 62,8 +/- 10,2 (range 46-76) years. Mean time from the diagnosis of RA to the start of dialysotherapy was 18,8 +/- 11,6 (range 5-40) years. Earlier the patients were treated with many disease modifying antirheumatic drugs (DMARDS) also with glucocorticosteroids and many nonsteroidal anti-inflammatory drugs. It means that they had rather aggressive type of RA. Amyloidosis was histological confirmed in 6 pts (4 F, 2 M). Peritoneal dialysis (PD) was the first choice therapy in 8 pts (2 on APD, 6 on CAPD). The main complication was increased incidence of peritonitis. 3 pts died on PD after 5, 9, 24 months (respectively) of CAPD treatment. 3 pts were transferred to HD after 5, 15, 18 (respectively) months of CAPD because of recurrent peritonitis. 2 pts up to date continue PD (one 12 months, the second 46 months on CAPD). In 5 pts who needed hemodialysis treatment there have been very serious problems with permanent vascular access formation. All used permanent indwelling catheters (Permcath). We concluded that: occurrence of ESRD in pts with RA was connected with aggressive type of disease. Pts with RA represent a dialysis group that is particularly prone to complications of PD (enteric peritonitis) and HD (vascular access problems). It seems to be connected with secondary vasculitis often found in pts with aggressive type of RA.

AAV2 production with optimized N/P ratio and PEI-mediated transfection results in low toxicity and high titer for in vitro and in vivo applications.

PubMed

Huang, Xinping; Hartley, Antja-Voy; Yin, Yishi; Herskowitz, Jeremy H; Lah, James J; Ressler, Kerry J

2013-11-01

The adeno-associated virus (AAV) is one of the most useful viral vectors for gene delivery for both in vivo and in vitro applications. A variety of methods have been established to produce and characterize recombinant AAV (rAAV) vectors; however most methods are quite cumbersome and obtaining consistently high titer can be problematic. This protocol describes a triple-plasmid co-transfection approach with 25 kDa linear polyethylenimine (PEI) in 293 T cells for the production of AAV serotype 2. Seventy-two hours post-transfection, supernatant and cells were harvested and purified by a discontinuous iodixanol density gradient ultracentrifugation, then dialyzed and concentrated with an Amicon 15 100,000 MWCO concentration unit. To optimize the protocol for AAV2 production using PEI, various N/P ratios and DNA amounts were compared. We found that an N/P ratio of 40 coupled with 1.05 μg DNA per ml of media (21 μg DNA/15 cm dish) was found to produce the highest yields for viral replication and assembly measured multiple ways. The infectious units, as determined by serial dilution, were between 1×10(8) and 2×10(9) IU/ml. The genomic titer of the viral stock was determined by qPCR and ranged from 2×10(12) to 6×10(13) VG/ml. These viral vectors showed high expression both in vivo within the brain and in vitro in cell culture. The use of linear 25 kDa polyethylenamine PEI as a transfection reagent is a simple, more cost-effective, and stable means of high-throughput production of high-titer AAV serotype 2. The use of PEI also eliminates the need to change cell medium post-transfection, lowering cost and workload, while producing high-titer, efficacious AAV2 vectors for routine gene transfer. Copyright © 2013 Elsevier B.V. All rights reserved.

Factors Associated with Bachelor Degree Attainment by Community College Transfer Students

ERIC Educational Resources Information Center

Mourad, Roger; Hong, JiHee

2011-01-01

Use of the community college as preparation for transfer to four-year institutions and bachelor degree attainment continues to be a critical means of access to higher learning for students from diverse backgrounds. What variables distinguish community college transfers to four-year institutions who earn a bachelor degree from transfers who do not…

Factors Contributing to the Upward Transfer of Baccalaureate Aspirants Beginning at Community Colleges. WISCAPE Working Paper

ERIC Educational Resources Information Center

Wang, Xueli

2010-01-01

Incorporating the psychological perspective, this study examines factors associated with the upward transfer of baccalaureate aspirants beginning at community colleges. Based on data from the National Education Longitudinal Study of 1988 and the Postsecondary Education Transcript Study, the study tests a logistic regression model to predict…

The Reverse Transfer Student: A Growing Factor in Higher Education

ERIC Educational Resources Information Center

Brimm, Jack; Achilles, C. M.

1976-01-01

A study of 195 reverse transfer students showed that following a poor academic performance at the university, the students achieved satisfactorily at the two-year college. Students who later returned to the university improved their grades with each quarter's course work. Factors associated with academic performance at the two institutions are…

Factors Associated with Transfer of Training in Workplace E-Learning

ERIC Educational Resources Information Center

Park, Ji-Hye; Wentling, Tim

2007-01-01

Purpose--The purpose of this study is to investigate the effect of factors associated with e-learning, particularly computer attitudes and usability, on transfer of training in workplace e-learning courses. Design/methodology/approach--This study relied on quantitative data obtained from four online survey questionnaires. The sample of this study…

When Rural Meets Urban: The Transfer Problem Chinese Pre-Service Teachers Face in Teaching Practice

ERIC Educational Resources Information Center

Ye, Wangbei

2016-01-01

Traditional teacher education's supposed failure to prepare prospective teachers for classroom realities (the transfer problem) is a widely discussed topic in the teacher education literature. Previous studies have focused on causal relationships between teaching and such factors as pre-service teacher education programmes, contextual factors in…

Comparison of Theoretical and Experimental Heat-Transfer Characteristics of Bodies of Revolution at Supersonic Speeds

NASA Technical Reports Server (NTRS)

Scherrer, Richard

1951-01-01

An investigation of the three important factors that determine convective heat-transfer characteristics at supersonic speeds, location boundary-layer transition, recovery factor, and heat-transfer parameter has been performed at Mach numbers from 1.49 to 1.18. The bodies of revolution that were tested had, in most cases, laminar boundary layers, and the test results have been compared with available theory. Boundary-layer transition was found to be affected by heat transfer. Adding heat to a laminar boundary layer caused transition to move forward on the test body, while removing heat caused transition to move rearward. These experimental results and the implications of boundary-layer-stability theory are in qualitative agreement.

Bidirectional associations in multiplication memory: conditions of negative and positive transfer.

PubMed

Campbell, Jamie I D; Robert, Nicole D

2008-05-01

A variety of experimental evidence indicates that the memory representation for multiplication facts (e.g., 6 x 9 = 54) incorporates bidirectional links with a forward association from factors to product and a reverse association from product to factors. Surprisingly, the authors did not find evidence in Experiment 1 of facilitative transfer-of-practice from multiplication (6 x 9 = ?) to factoring (54 = ? x ?); in fact, multiplication practice produced item-specific interference with factoring. Similarly, the authors found no evidence in Experiment 2 that repetition of specific factoring problems (54 = ? x ?) facilitated performance of corresponding multiplication problems (6 x 9 = ?). In Experiment 3, participants practiced both multiplication and factoring and presented facilitative transfer in both directions. Thus, bidirectional facilitation occurred if both operations were practiced, but interference occurred when only one operation was practiced. We propose that this seemingly paradoxical behavior occurs because it is adaptive for the bidirectional retrieval structure to retain operational flexibility in the context of practicing both operations, whereas it is adaptive to specialize the memory representation for the practiced operation (i.e., factoring or multiplication) when only one operation is practiced.

Factors affecting the efficiency of embryo transfer in the domestic ferret (Mustela putorius furo).

PubMed

Li, Ziyi; Sun, Xingshen; Chen, Juan; Leno, Gregory H; Engelhardt, John F

2006-07-15

Embryo transfer (ET) to recipient females is a foundational strategy for a number of assisted reproductive technologies, including cloning by somatic cell nuclear transfer. In an attempt to develop efficient ET in domestic ferrets, factors affecting development of transferred embryo were investigated. Unilateral and bilateral transfer of zygotes or blastocysts in the oviduct or uterus was evaluated in recipient nulliparous or primiparous females. Developing fetuses were collected from recipient animals 21 days post-copulation and examined. The percentage of fetal formation was different (P<0.05) for unilateral and bilateral transfer of zygotes (71%) in nulliparous females with bilateral transfer (56%) in primiparous recipients. The percentage (90%) of fetal formation in nulliparous recipients following unilateral transfer of blastocysts was higher (P<0.05) than that observed in primiparous recipients with bilateral ET (73%). Notably, the percentage of fetal formation was higher (P<0.05) when blastocyts were transferred as compared to zygotes (90% versus 71%). Transuterine migration of embryos occurred following all unilateral transfers and also in approximately 50% of bilateral transfers with different number of embryos in each uterine horn. These data will help to facilitate the development of assisted reproductive strategies in the ferret and could lead to the use of this species for modeling human disease and for conservation of the endangered Mustelidae species such as black-footed ferret and European mink.

Factors affecting the efficiency of embryo transfer in the domestic ferret (Mustela putorius furo)

PubMed Central

Li, Ziyi; Sun, Xingshen; Chen, Juan; Leno, Gregory H.; Engelhardt, John F.

2007-01-01

Embryo transfer (ET) to recipient females is a foundational strategy for a number of assisted reproductive technologies, including cloning by somatic cell nuclear transfer. In an attempt to develop efficient ET in domestic ferrets, factors affecting development of transferred embryo were investigated. Unilateral and bilateral transfer of zygotes or blastocysts in the oviduct or uterus was evaluated in recipient nulliparous or primiparous females. Developing fetuses were collected from recipient animals 21 days post-copulation and examined. The percentage of fetal formation was different (P < 0.05) for unilateral and bilateral transfer of zygotes (71%) in nulliparous females with bilateral transfer (56%) in primiparous recipients. The percentage (90%) of fetal formation in nulliparous recipients following unilateral transfer of blastocysts was higher (P < 0.05) than that observed in primiparous recipients with bilateral ET (73%). Notably, the percentage of fetal formation was higher (P < 0.05) when blastocyts were transferred as compared to zygotes (90% versus 71%). Transuterine migration of embryos occurred following all unilateral transfers and also in approximately 50% of bilateral transfers with different number of embryos in each uterine horn. These data will help to facilitate the development of assisted reproductive strategies in the ferret and could lead to the use of this species for modeling human disease and for conservation of the endangered Mustelidae species such as black-footed ferret and European mink. PMID:16330092

10 CFR 626.7 - Royalty transfer and exchange.

Code of Federal Regulations, 2011 CFR

2011-01-01

... DEPARTMENT OF ENERGY (CONTINUED) SALES REGULATION PROCEDURES FOR ACQUISITION OF PETROLEUM FOR THE STRATEGIC PETROLEUM RESERVE § 626.7 Royalty transfer and exchange. (a) General. DOE shall conduct royalty transfers... supply or refining capability, logistical problems for moving petroleum products, macroeconomic factors...

Abdominal ectopic pregnancy after in vitro fertilization and single embryo transfer: a case report and systematic review.

PubMed

Yoder, Nicole; Tal, Reshef; Martin, J Ryan

2016-10-19

Ectopic pregnancy is the leading cause of maternal morbidity and mortality during the first trimester and the incidence increases dramatically with assisted-reproductive technology (ART), occurring in approximately 1.5-2.1 % of patients undergoing in-vitro fertilization (IVF). Abdominal ectopic pregnancy is a rare yet clinically significant form of ectopic pregnancy due to potentially high maternal morbidity. While risk factors for ectopic pregnancy after IVF have been studied, very little is known about risk factors specific for abdominal ectopic pregnancy. We present a case of a 30 year-old woman who had an abdominal ectopic pregnancy following IVF and elective single embryo transfer, which was diagnosed and managed by laparoscopy. We performed a systematic literature search to identify case reports of abdominal or heterotopic abdominal ectopic pregnancies after IVF. A total of 28 cases were identified. Patients' ages ranged from 23 to 38 (Mean 33.2, S.D. = 3.2). Infertility causes included tubal factor (46 %), endometriosis (14 %), male factor (14 %), pelvic adhesive disease (7 %), structural/DES exposure (7 %), and unexplained infertility (14 %). A history of ectopic pregnancy was identified in 39 % of cases. A history of tubal surgery was identified in 50 % of cases, 32 % cases having had bilateral salpingectomy. Transfer of two embryos or more (79 %) and fresh embryo transfer (71 %) were reported in the majority of cases. Heterotopic abdominal pregnancy occurred in 46 % of cases while 54 % were abdominal ectopic pregnancies. Our systematic review has revealed several trends in reported cases of abdominal ectopic pregnancy after IVF including tubal factor infertility, history of tubal ectopic and tubal surgery, higher number of embryos transferred, and fresh embryo transfers. These are consistent with known risk factors for ectopic pregnancy following IVF. Further research focusing on more homogenous population may help in better characterizing this rare IVF complication and its risks.

Soil to rice transfer factors for (226)Ra, (228)Ra, (210)Pb, (40)K and (137)Cs: a study on rice grown in India.

PubMed

Karunakara, N; Rao, Chetan; Ujwal, P; Yashodhara, I; Kumara, Sudeep; Ravi, P M

2013-04-01

India is the second largest producer of rice (Oryza sativa L.) in the world and rice is an essential component of the diet for a majority of the population in India. However, detailed studies aimed at the evaluation of radionuclide transfer factors (F(v)) for the rice grown in India are almost non-existent. This paper presents the soil to rice transfer factors for natural ((226)Ra, (228)Ra, (40)K, and (210)Pb) and artificial ((137)Cs) radionuclides for rice grown in natural field conditions on the West Coast of India. A rice field was developed very close to the Kaiga nuclear power plant and the water required for this field was drawn from the cooling water discharge canal of the power plant. For a comparative study of the radionuclide transfer factors, rice samples were also collected from the rice fields of nearby villages. The study showed that the (226)Ra and (228)Ra activity concentrations were below detection levels in different organs of the rice plant. The soil to un-hulled rice grain (40)K transfer factor varied in the range of 6.5 × 10(-1) to 2.9 with a mean of 0.15 × 10(1), and of (210)Pb varied in the range of <1.2 × 10(-2) to 8.1 × 10(-1) with a mean of 1.4 × 10(-1), and of (137)Cs varied in the range of 6.6 × 10(-2) to 3.4 × 10(-1) with a mean of 2.1 × 10(-1). The mean values of un-hulled grain to white rice processing retention factors (F(r)) were 0.12 for (40)K, 0.03 for (210)Pb, and 0.14 for (137)Cs. Using these processing retention factors, the soil to white rice transfer factors were estimated and these were found to have mean values of 1.8 × 10(-1), 4.2 × 10(-3), and 3.0 × 10(-2) for (40)K, (210)Pb, and (137)Cs, respectively. The study has shown that the transfer of (40)K was higher for above the ground organs than for the root, but (210)Pb and (137)Cs were retained in the root and their transfer to above the ground organs of the rice plant is significantly lower. Copyright © 2012 Elsevier Ltd. All rights reserved.

Understanding the associations between modifying factors, individual health beliefs, and hemodialysis patients' adherence to a low-phosphorus diet.

PubMed

Elliott, John O; Ortman, Carl; Almaani, Salem; Lee, Yun Hui; Jordan, Kim

2015-03-01

Hyperphosphatemia in end-stage renal disease is associated with significant morbidity and mortality. Because phosphorus is not effectively dialyzed, dietary adherence remains a significant problem. Previous studies have examined the health belief model, but none have looked at stages of change and dietary adherence in patients undergoing hemodialysis (HD). Cross-sectional survey. Three dialysis centers in Columbus, Ohio, between August 2012 and March 2013. English-speaking patients age 18 or older on HD without dementia or developmental delay. None. Associations between dietary adherence based on the Precaution Adoption Process Model (stages of change) and serum phosphorus levels via a conceptual model incorporating modifying factors and individual health beliefs. Ninety-five patients completed the survey; 59 (62%) endorsed adherence to a low-phosphorus diet and 32 (34%) had phosphorus values ≤5.5 mg/dL. Modifying factors associated with diet adherence included nonminority status odds ratio (OR), 95%CI 8.99 (1.08-74.60), greater level of education OR 18.23 (1.62-205.00), better quality of life OR 9.28 (1.35-63.71), and time on dialysis OR 1.04 (1.01-1.07). Individual health beliefs associated with diet adherence included perceived benefits OR 3.18 (1.47-6.88) and self-efficacy OR 1.22 (1.09-1.38). Modifying factors associated with phosphorus control included: age OR 0.94 (0.90-0.99), minority status OR 0.11 (0.02-0.68), greater level of education OR 6.60 (1.41-31.04), knowledge about chronic kidney disease OR 1.48 (1.03-2.13), and time on dialysis OR 0.98 (0.96-0.99). Individual health beliefs associated with phosphorus control included self-efficacy OR 1.08 (1.01-1.16). HD clinicians and educators may obtain better results with dietary adherence and phosphorus control if they focus not only toward disease and dietary education but also on understanding modifying factors and individual health beliefs. Assessing where the patient is with regard to stages of change may assist health care providers in better matching interventions that build patients' self-efficacy. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

A Novel Adaptive H∞ Filtering Method with Delay Compensation for the Transfer Alignment of Strapdown Inertial Navigation Systems.

PubMed

Lyu, Weiwei; Cheng, Xianghong

2017-11-28

Transfer alignment is always a key technology in a strapdown inertial navigation system (SINS) because of its rapidity and accuracy. In this paper a transfer alignment model is established, which contains the SINS error model and the measurement model. The time delay in the process of transfer alignment is analyzed, and an H∞ filtering method with delay compensation is presented. Then the H∞ filtering theory and the robust mechanism of H∞ filter are deduced and analyzed in detail. In order to improve the transfer alignment accuracy in SINS with time delay, an adaptive H∞ filtering method with delay compensation is proposed. Since the robustness factor plays an important role in the filtering process and has effect on the filtering accuracy, the adaptive H∞ filter with delay compensation can adjust the value of robustness factor adaptively according to the dynamic external environment. The vehicle transfer alignment experiment indicates that by using the adaptive H∞ filtering method with delay compensation, the transfer alignment accuracy and the pure inertial navigation accuracy can be dramatically improved, which demonstrates the superiority of the proposed filtering method.

Transferring Learning to the Workplace. Seventeen Case Studies from the Real World of Training. In Action Series.

ERIC Educational Resources Information Center

Broad, Mary L., Ed.

Organized in three parts, this book contains an introductory chapter and 17 case studies selected to show transfer applications in a wide range of organizational settings. In part 1, two chapters review the rationale, context, and research relating to transfer: "Transfer Concepts and Research Overview" (Mary Broad); and "Success Factors in…

Transfer from Two-Year to Four-Year College: An Analysis of Gender Differences.

ERIC Educational Resources Information Center

Surette, Brian J.

2001-01-01

Nearly two-thirds of all students attending 2-year colleges transfer to 4-year colleges by age 25. This paper shows that women are less likely than men to transfer; women who do transfer are less apt to earn a bachelor's degree, even after controlling for marital status and other factors. (Contains 18 references.) (MLH)

The Role of Teams, Culture, and Capacity in the Transfer of Organizational Practices

ERIC Educational Resources Information Center

Lucas, Leyland M.

2010-01-01

Purpose: Transferring organizational practices requires an understanding not only of what is being transferred but also of what is needed to ensure that the transfer is successful. In line with this thinking, the purpose of this study is to examine three factors that are crucial parts of this mechanism: use of teams, culture, and capacity.…

Efficiency of porcine somatic cell nuclear transfer – a retrospective study of factors related to embryo recipient and embryos transferred

PubMed Central

Huang, Yongye; Ouyang, Hongsheng; Yu, Hao; Lai, Liangxue; Pang, Daxin; Li, Zhanjun

2013-01-01

Summary The successful generation of pigs via somatic cell nuclear transfer depends on reducing risk factors in several aspects. To provide an overview of some influencing factors related to embryo transfer, the follow-up data related to cloned pig production collected in our laboratory was examined. (i) Spring showed a higher full-term pregnancy rate compared with winter (33.6% vs 18.6%, P = 0.006). Furthermore, a regression equation can be drawn between full-term pregnancy numbers and pregnancy numbers in different months (y = 0.692x−3.326). (ii) There were no significant differences detected in the number of transferred embryos between surrogate sows exhibiting full-term development compared to those that did not. (iii) Non-ovulating surrogate sows presented a higher percentage of full-term pregnancies compared with ovulating sows (32.0% vs 17.5%, P = 0.004; respectively). (iv) Abortion was most likely to take place between Day 27 to Day 34. (v) Based on Life Table Survival Analysis, delivery in normally fertilized and surrogate sows is expected to be completed before Day 117 or Day 125, respectively. Additionally, the length of pregnancy in surrogate sows was negatively correlated with the average litter size, which was not found for normally fertilized sows. In conclusion, performing embryo transfer in appropriate seasons, improving the quality of embryos transferred, optimizing the timing of embryo transfer, limiting the occurrence of abortion, combined with ameliorating the management of delivery, is expected to result in the harvest of a great number of surviving cloned piglets. PMID:24244859

Shape-Independent Limits to Near-Field Radiative Heat Transfer

NASA Astrophysics Data System (ADS)

Miller, Owen D.; Johnson, Steven G.; Rodriguez, Alejandro W.

2015-11-01

We derive shape-independent limits to the spectral radiative heat transfer rate between two closely spaced bodies, generalizing the concept of a blackbody to the case of near-field energy transfer. Through conservation of energy and reciprocity, we show that each body of susceptibility χ can emit and absorb radiation at enhanced rates bounded by |χ |2/Im χ , optimally mediated by near-field photon transfer proportional to 1 /d2 across a separation distance d . Dipole-dipole and dipole-plate structures approach restricted versions of the limit, but common large-area structures do not exhibit the material enhancement factor and thus fall short of the general limit. By contrast, we find that particle arrays interacting in an idealized Born approximation (i.e., neglecting multiple scattering) exhibit both enhancement factors, suggesting the possibility of orders-of-magnitude improvement beyond previous designs and the potential for radiative heat transfer to be comparable to conductive heat transfer through air at room temperature, and significantly greater at higher temperatures.

Identification of factors that affect the adoption of an ergonomic intervention among Emergency Medical Service workers.

PubMed

Weiler, Monica R; Lavender, Steven A; Crawford, J Mac; Reichelt, Paul A; Conrad, Karen M; Browne, Michael W

2012-01-01

This study explored factors contributing to intervention adoption decisions among Emergency Medical Service (EMS) workers. Emergency Medical Service workers (n = 190), from six different organisations, participated in a two-month longitudinal study following the introduction of a patient transfer-board (also known as slide-board) designed to ease lateral transfers of patients to and from ambulance cots. Surveys administered at baseline, after one month and after two months sampled factors potentially influencing the EMS providers' decision process. 'Ergonomics Advantage' and 'Patient Advantage' entered into a stepwise regression model predicting 'intention to use' at the end of month one (R (2 )= 0.78). After the second month, the stepwise regression indicated only two factors were predictive of intention to use: 'Ergonomics Advantage,' and 'Endorsed by Champions' (R (2 )= 0.58). Actual use was predicted by: 'Ergonomics Advantage' and 'Previous Tool Experience.' These results relate to key concepts identified in the diffusion of innovation literature and have the potential to further ergonomics intervention adoption efforts. Practitioner Summary. This study explored factors that potentially facilitate the adoption of voluntarily used ergonomics interventions. EMS workers were provided with foldable transfer-boards (slideboards) designed to reduce the physical demands when laterally transferring patients. Factors predictive of adoption measures included perceived ergonomics advantage, the endorsement by champions, and prior tool experience.

A Transfer Learning Approach for Applying Matrix Factorization to Small ITS Datasets

ERIC Educational Resources Information Center

Voß, Lydia; Schatten, Carlotta; Mazziotti, Claudia; Schmidt-Thieme, Lars

2015-01-01

Machine Learning methods for Performance Prediction in Intelligent Tutoring Systems (ITS) have proven their efficacy; specific methods, e.g. Matrix Factorization (MF), however suffer from the lack of available information about new tasks or new students. In this paper we show how this problem could be solved by applying Transfer Learning (TL),…

What's Working: Program Factors Influencing California Community College Basic Skills Mathematics Students' Advancement to Transfer Level

ERIC Educational Resources Information Center

Fiero, Diane M.

2013-01-01

Purpose: The purpose of this study was to determine which basic skills program factors were exhibited by successful basic skills programs that helped students advance to transfer-level mathematics. This study specifically examined California community college basic skills programs that assist students who place in mathematics courses 2 levels…

The 12th Curative Factor: Love as an Agent of Healing in Group Psychotherapy.

ERIC Educational Resources Information Center

Bemak, Fred; Epp, Lawrence R.

1996-01-01

Proposes love as a curative factor in group psychotherapy. Transference within a group may originate with needs and desires for love. By unmasking transference, subsequent healing may arise from a process of mourning in which group members recognize how their projection of past love onto other group members and onto the psychotherapist is…

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadena, M. S. Reyes; Chapul, L. Sanchez; Perez, Javier

2008-08-11

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-{beta}) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animalsmore » subjected to ELF together with the transfer factor.« less

A review of factors affecting the transfer of sexual and reproductive health training into practice in low and lower-middle income country humanitarian settings.

PubMed

Beek, Kristen; Dawson, Angela; Whelan, Anna

2017-01-01

A lack of access to sexual and reproductive health (SRH) care is the leading cause of morbidity and mortality among displaced women and girls of reproductive age. Efforts to address this public health emergency in humanitarian settings have included the widespread delivery of training programmes to address gaps in health worker capacity for SRH. There remains a lack of data on the factors which may affect the ability of health workers to apply SRH knowledge and skills gained through training programmes in humanitarian contexts. We searched four electronic databases and ten key organizations' websites to locate literature on SRH training for humanitarian settings in low and lower-middle income countries. Papers were examined using content analysis to identify factors which contribute to health workers' capacity to transfer SRH knowledge, skills and attitudes learned in training into practice in humanitarian settings. Seven studies were included in this review. Six research papers focused on the response stage of humanitarian crises and five papers featured the disaster context of conflict. A range of SRH components were addressed including maternal, newborn health and sexual violence. The review identified factors, including appropriate resourcing, organisational support and confidence in health care workers that were found to facilitate the transfer of learning. The findings suggest the presence of factors that moderate the transfer of training at the individual, training, organisational, socio-cultural, political and health system levels. Supportive strategies are necessary to best assist trainees to apply newly acquired knowledge and skills in their work settings. These interventions must address factors that moderate the success of learning transfer. Findings from this review suggest that these are related to the individual trainee, the training program itself and the workplace as well as the broader environmental context. Organisations which provide SRH training for humanitarian emergencies should work to identify the system of moderating factors that affect training transfer in their setting and employ evidence-based strategies to ameliorate these.

An exploration of the perceived factors that affect the learning and transfer of skills taught to student midwives.

PubMed

Longworth, Mary K

2013-08-01

the aim of this study was to examine the attitudes of student midwives towards skills training and practise. The objectives were to explore the factors in the skills laboratory environment and in clinical practice which affect how successfully student midwives transfer into clinical practice the various skills they have learnt in preparation for an Objective Structured Clinical Examination. a review of the background literature revealed that there were many variables related to successful transfer of skills in general but there appeared to be a gap around perceived factors affecting transfer of skills of student midwives. a mixed methods design was conducted using both questionnaires and semi-structured interviews between June and August 2010. questionnaires were administered to all midwifery students at one university in Wales. These were later followed by semi-structured interviews for 6 student midwives who were purposively selected from all year groups. the results from the questionnaires revealed that a majority of students had positive attitudes to educators and mentors and to their skills acquisition experience in the skills laboratory and to the available opportunities to practise in clinical practice. Although students believed in the transferability of skills from the laboratory setting to clinical practice, a majority thought that clinical practice provided them with a better opportunity to learn clinical skills. The semi-structured interviews demonstrated that facilitating factors in the skills laboratory included having adequate instruction as well as having a designated space. Hindering factors included unrealistic models and equipment. In clinical practice, facilitating factors included having the opportunities to practise skills and support and feedback from the mentor. Hindering factors included deficits in the student-mentor relationship. this study highlighted that midwifery students must be adequately prepared to carry out clinical skills competently and effectively. Educators and mentors must provide adequate support and feedback to promote transfer of knowledge and skills into the workplace to optimise high standards of care for women and their babies. Copyright © 2012 Elsevier Ltd. All rights reserved.

How do laboratory embryo transfer techniques affect IVF outcomes? A review of current literature.

PubMed

Sigalos, George; Triantafyllidou, Olga; Vlahos, Nikos

2017-04-01

Over the last few years, many studies have focused on embryo selection methods, whereas little attention has been given to the standardization of the procedure of embryo transfer. In this review, several parameters of the embryo transfer procedure are examined, such as the: (i) culture medium volume and loading technique; (ii) syringe and catheters used for embryo transfer; (iii) viscosity and composition of the embryo transfer medium; (iv) environment of embryo culture; (v) timing of embryo transfer; (vi) and standardization of the embryo transfer techniques. The aim of this manuscript is to review these factors and compare the existing embryo transfer techniques and highlight the need for better embryo transfer standardization.

Phosphorus transfer in surface runoff from intensive pasture systems at various scales: a review.

PubMed

Dougherty, Warwick J; Fleming, Nigel K; Cox, Jim W; Chittleborough, David J

2004-01-01

Phosphorus transfer in runoff from intensive pasture systems has been extensively researched at a range of scales. However, integration of data from the range of scales has been limited. This paper presents a conceptual model of P transfer that incorporates landscape effects and reviews the research relating to P transfer at a range of scales in light of this model. The contribution of inorganic P sources to P transfer is relatively well understood, but the contribution of organic P to P transfer is still relatively poorly defined. Phosphorus transfer has been studied at laboratory, profile, plot, field, and watershed scales. The majority of research investigating the processes of P transfer (as distinct from merely quantifying P transfer) has been undertaken at the plot scale. However, there is a growing need to integrate data gathered at a range of scales so that more effective strategies to reduce P transfer can be identified. This has been hindered by the lack of a clear conceptual framework to describe differences in the processes of P transfer at the various scales. The interaction of hydrological (transport) factors with P source factors, and their relationship to scale, require further examination. Runoff-generating areas are highly variable, both temporally and spatially. Improvement in the understanding and identification of these areas will contribute to increased effectiveness of strategies aimed at reducing P transfers in runoff. A thorough consideration of scale effects using the conceptual model of P transfer outlined in this paper will facilitate the development of improved strategies for reducing P losses in runoff.

A Qualitative Study of Two-To-Four-Year Transfer Practices in California Community Colleges: An Analysis of Seven Case Studies Featuring Colleges with Consistently Higher-than-Expected Transfer Rates, Fall 2008

ERIC Educational Resources Information Center

Mery, Pamela; Schiorring, Eva

2008-01-01

Which factors promote transfer from community colleges to four-year colleges and universities? What can individuals learn about transfer from tracking cohorts of students? What can they learn from studying colleges that have a strong track record of transferring students? These questions are at the center of a study funded in 2007 by the…

Largely ignored: the impact of the threshold value for a QALY on the importance of a transferability factor.

PubMed

Vemer, Pepijn; Rutten-van Mölken, Maureen P M H

2011-10-01

Recently, several checklists systematically assessed factors that affect the transferability of cost-effectiveness (CE) studies between jurisdictions. The role of the threshold value for a QALY has been given little consideration in these checklists, even though the importance of a factor as a cause of between country differences in CE depends on this threshold. In this paper, we study the impact of the willingness-to-pay (WTP) per QALY on the importance of transferability factors in the case of smoking cessation support (SCS). We investigated, for several values of the WTP, how differences between six countries affect the incremental net monetary benefit (INMB) of SCS. The investigated factors were demography, smoking prevalence, mortality, epidemiology and costs of smoking-related diseases, resource use and unit costs of SCS, utility weights and discount rates. We found that when the WTP decreased, factors that mainly affect health outcomes became less important and factors that mainly effect costs became more important. With a WTP below 1,000, the factors most responsible for between country differences in INMB were resource use and unit costs of SCS and the costs of smoking-related diseases. Utility values had little impact. At a threshold above 10,000, between country differences were primarily due to different discount rates, utility weights and epidemiology of smoking-related diseases. Costs of smoking-related diseases had little impact. At all thresholds, demography had little impact. We concluded that, when judging the transferability of a CE study, we should consider the between country differences in WTP threshold values.

Analogical Transfer from a Simulated Physical System

ERIC Educational Resources Information Center

Day, Samuel B.; Goldstone, Robert L.

2011-01-01

Previous research has consistently found that spontaneous analogical transfer is strongly tied to concrete and contextual similarities between the cases. However, that work has largely failed to acknowledge that the relevant factor in transfer is the similarity between individuals' mental representations of the situations rather than the overt…

Heavy Metal Bioaccumulation Capability of Woody Plants in Mine wasteland of Karst Areas

NASA Astrophysics Data System (ADS)

Xiuru, Wang; Zhongliang, Huang; Xuan, Zhang; Zijian, Wu

2017-04-01

The bioaccumulation capability and transfer characteristics of Pb, Zn, Cu and Cd in soil and 6 different woody plants collected from a typical lead-zinc mine wasteland of Karst area, Hunan province were investigated, including Cunninghamia lanceolata(Lamb.) Hook., Swida wilsoniana (Wanger.), Koelreuteria paniculata, Paulownia., Cinnamomum camphora (L.) Presl., and Sapium sebiferum (L.) Roxb. The results showed that the 6 plants could adapt to the heavy metal polluted environment, and there was a positive correlation between the heavy metal content in plants and soil.Swida wilsoniana (Wanger.) and Sapium sebiferum (L.) Roxb. had the largest Pb bioaccumulation factor of 0.03; Paulownia. had the highest Zn bioaccumulation factor of 0.37; the largest Pb transfer factor of 1.31 were found in Koelreuteria paniculata; and Zn transfer factor of Paulownia. reached 1.45. These 4 woody plants are suitable for phytoremediation of mine wasteland of Karst areas.

Energy transfer mechanism and probability analysis of submarine pipe laterally impacted by dropped objects

NASA Astrophysics Data System (ADS)

Liang, Jing; Yu, Jian-xing; Yu, Yang; Lam, W.; Zhao, Yi-yu; Duan, Jing-hui

2016-06-01

Energy transfer ratio is the basic-factor affecting the level of pipe damage during the impact between dropped object and submarine pipe. For the purpose of studying energy transfer and damage mechanism of submarine pipe impacted by dropped objects, series of experiments are designed and carried out. The effective yield strength is deduced to make the quasi-static analysis more reliable, and the normal distribution of energy transfer ratio caused by lateral impact on pipes is presented by statistic analysis of experimental results based on the effective yield strength, which provides experimental and theoretical basis for the risk analysis of submarine pipe system impacted by dropped objects. Failure strains of pipe material are confirmed by comparing experimental results with finite element simulation. In addition, impact contact area and impact time are proved to be the major influence factors of energy transfer by sensitivity analysis of the finite element simulation.

Interrelationships of metal transfer factor under wastewater reuse and soil pollution.

PubMed

Papaioannou, D; Kalavrouziotis, I K; Koukoulakis, P H; Papadopoulos, F; Psoma, P

2018-06-15

The transfer of heavy metals under soil pollution wastewater reuse was studied in a Greenhouse experiment using a randomized block design, including 6 treatments of heavy metals mixtures composed of Zn, Mn, Cd, Co, Cu, Cr, Ni, and Pb, where each metal was taking part in the mixture with 0, 10, 20, 30, 40, 50 mg/kg respectively, in four replications. The Beta vulgaris L (beet) was used as a test plant. It was found that the metal transfer factors were statistically significantly related to the: (i) DTPA extractable soil metals, (ii) the soil pollution level as assessed by the pollution indices, (iii) the soil pH, (iv) the beet dry matter yield and (v) the interactions between the heavy metals in the soil. It was concluded that the Transfer Factor is subjected to multifactor effects and its real nature is complex, and there is a strong need for further study for the understanding of its role in metal-plant relationships. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transfer of Training: Does It Truly Happen?: An Examination of Support, Instrumentality, Retention and Learner Readiness on the Transfer Motivation and Transfer of Training

ERIC Educational Resources Information Center

Bhatti, Muhammad Awais; Battour, Mohamed Mohamed; Sundram, Veera Pandiyan Kaliani; Othman, Akmal Aini

2013-01-01

Purpose: The purpose of this study is to highlight the importance of selected environmental, situational and individual factors in the training transfer process. Design/methodology/approach: This study proposes and tests a framework via structural equation modelling by including supervisor and peer support, instrumentality and learner readiness on…

Environmental factors influencing gene transfer agent (GTA) mediated transduction in the subtropical ocean.

PubMed

McDaniel, Lauren D; Young, Elizabeth C; Ritchie, Kimberly B; Paul, John H

2012-01-01

Microbial genomic sequence analyses have indicated widespread horizontal gene transfer (HGT). However, an adequate mechanism accounting for the ubiquity of HGT has been lacking. Recently, high frequencies of interspecific gene transfer have been documented, catalyzed by Gene Transfer Agents (GTAs) of marine α-Proteobacteria. It has been proposed that the presence of bacterial genes in highly purified viral metagenomes may be due to GTAs. However, factors influencing GTA-mediated gene transfer in the environment have not yet been determined. Several genomically sequenced strains containing complete GTA sequences similar to Rhodobacter capsulatus (RcGTA, type strain) were screened to ascertain if they produced putative GTAs, and at what abundance. Five of nine marine strains screened to date spontaneously produced virus-like particles (VLP's) in stationary phase. Three of these strains have demonstrated gene transfer activity, two of which were documented by this lab. These two strains Roseovarius nubinhibens ISM and Nitratireductor 44B9s, were utilized to produce GTAs designated RnGTA and NrGTA and gene transfer activity was verified in culture. Cell-free preparations of purified RnGTA and NrGTA particles from marked donor strains were incubated with natural microbial assemblages to determine the level of GTA-mediated gene transfer. In conjunction, several ambient environmental parameters were measured including lysogeny indicated by prophage induction. GTA production in culture systems indicated that approximately half of the strains produced GTA-like particles and maximal GTA counts ranged from 10-30% of host abundance. Modeling of GTA-mediated gene transfer frequencies in natural samples, along with other measured environmental variables, indicated a strong relationship between GTA mediated gene transfer and the combined factors of salinity, multiplicity of infection (MOI) and ambient bacterial abundance. These results indicate that GTA-mediated HGT in the marine environment with the strains examined is favored during times of elevated bacterial and GTA abundance as well as in areas of higher salinity.

Environmental Factors Influencing Gene Transfer Agent (GTA) Mediated Transduction in the Subtropical Ocean

PubMed Central

McDaniel, Lauren D.; Young, Elizabeth C.; Ritchie, Kimberly B.; Paul, John H.

2012-01-01

Microbial genomic sequence analyses have indicated widespread horizontal gene transfer (HGT). However, an adequate mechanism accounting for the ubiquity of HGT has been lacking. Recently, high frequencies of interspecific gene transfer have been documented, catalyzed by Gene Transfer Agents (GTAs) of marine α-Proteobacteria. It has been proposed that the presence of bacterial genes in highly purified viral metagenomes may be due to GTAs. However, factors influencing GTA-mediated gene transfer in the environment have not yet been determined. Several genomically sequenced strains containing complete GTA sequences similar to Rhodobacter capsulatus (RcGTA, type strain) were screened to ascertain if they produced putative GTAs, and at what abundance. Five of nine marine strains screened to date spontaneously produced virus-like particles (VLP's) in stationary phase. Three of these strains have demonstrated gene transfer activity, two of which were documented by this lab. These two strains Roseovarius nubinhibens ISM and Nitratireductor 44B9s, were utilized to produce GTAs designated RnGTA and NrGTA and gene transfer activity was verified in culture. Cell-free preparations of purified RnGTA and NrGTA particles from marked donor strains were incubated with natural microbial assemblages to determine the level of GTA-mediated gene transfer. In conjunction, several ambient environmental parameters were measured including lysogeny indicated by prophage induction. GTA production in culture systems indicated that approximately half of the strains produced GTA-like particles and maximal GTA counts ranged from 10–30% of host abundance. Modeling of GTA-mediated gene transfer frequencies in natural samples, along with other measured environmental variables, indicated a strong relationship between GTA mediated gene transfer and the combined factors of salinity, multiplicity of infection (MOI) and ambient bacterial abundance. These results indicate that GTA-mediated HGT in the marine environment with the strains examined is favored during times of elevated bacterial and GTA abundance as well as in areas of higher salinity. PMID:22905268

IUS prerelease alignment

NASA Technical Reports Server (NTRS)

Evans, F. A.

1978-01-01

Space shuttle orbiter/IUS alignment transfer was evaluated. Although the orbiter alignment accuracy was originally believed to be the major contributor to the overall alignment transfer error, it was shown that orbiter alignment accuracy is not a factor affecting IUS alignment accuracy, if certain procedures are followed. Results are reported of alignment transfer accuracy analysis.

Learning Transfer: The Views of Practitioners in Ireland

ERIC Educational Resources Information Center

Donovan, Paul; Darcy, David P.

2011-01-01

Considerable expenditure on human resource development (HRD) has not necessarily resulted in a significant impact on organizational performance, and research suggests that the failure to transfer learning may be an important explanation. The search for factors affecting transfer has been extensive, as shown in Grossman and Salas's article in this…

Impact of Individual Perception of Organizational Culture on the Learning Transfer Environment

ERIC Educational Resources Information Center

Chatterjee, Aindrila; Pereira, Arun; Bates, Reid

2018-01-01

This research is an empirical study of the relationship between organization culture, as perceived by employees, and the work-environment-related learning transfer factors in organizations, which we call learning transfer environment (LTE). To measure perceptions of organization culture, we use the Organizational Culture Assessment Instrument and…

Convergent and Divergent Validity of the Learning Transfer System Inventory

ERIC Educational Resources Information Center

Holton, Elwood F., III; Bates, Reid A.; Bookter, Annette I.; Yamkovenko, V. Bogdan

2007-01-01

The Learning Transfer System Inventory (LTSI) was developed to identify a select set of factors with the potential to substantially enhance or inhibit transfer of learning to the work environment. It has undergone a variety of validation studies, including construct, criterion, and crosscultural studies. However, the convergent and divergent…

Perceptions of a Learning Organization and Factors within the Work Environment That Influence Transfer of Training in Law Enforcement

ERIC Educational Resources Information Center

Hunter-Johnson, Yvonne

2012-01-01

The purpose of this study was to determine law enforcement officers' perception of factors within the workplace that influence transfer of training and their perception of the organization being a learning organization. The study actually had three parts. First, it intended to investigate the perception of law enforcement officers regarding…

[Factors affecting the clinical pregnancy rate in an in vitro fertilization and embryo transfer program].

PubMed

Zhang, L; Wei, Z; Liu, P

1998-12-01

To analyze the various factors in an in vitro fertilization and embryo transfer (IVF-ET) program which may affect the clinical pregnacy rate. A retrospective study was done on 559 IVF-ET cycles from 1992-Nov. 1995. The indication for treatment was bilateral tubal blockage. The chi 2 analysis of single factor variants with SPSS-PC + V3.0 was used for statistics. The overall clinical pregnancy rate in 559 cycles was 21.6%. The cause of tubal blockage due to tuberculoses consisted of 28.4%, and 34.9% of secondary sterility had the history of artificial abortion. The changes of environment, the different causes of tubal blockage, the history of previous intrauterine pregnancy did not affect the clinical pregnancy rate. When the number of embryos transferred increased to 5, the clinical pregnancy rate was highest 32.5%. The cumulative embryo score or embryo quality was related significantly with clinical pregnancy rate. The number and quality of embryos transferred are important factors affecting the clinical pregnancy rate. However, measures to prevent high-order multiple pregnancy and studies on the survival potential of embryos besides their morphology should be emphasized.

The role of the University Licensing Office in transferring intellectual property to industry

NASA Technical Reports Server (NTRS)

Preston, John T.

1992-01-01

Universities in the US have a significant impact on business through the transfer of technology. This transfer of technology takes various forms, including faculty communications, faculty consulting activities, and the direct transfer of technology through the licensing of patents, copyrights, and other intellectual property to industry. The topics discussed include the following: background of the MIT Technology Licensing Office (TLO), goals of the MIT TLO, MIT's technology transfer philosophy, and important factors for success in new company formation.

General and specific factors in the intersensory transfer of form.

NASA Technical Reports Server (NTRS)

Clark, J. L.; Warm, J. S.; Schumsky, D. A.

1972-01-01

This study assessed the relative contributions of specific and nonspecific components to intersensory transfer between vision and touch. A paired-associate paradigm was used in which visual metric figures and their tactual analogs served as stimuli, and familiar adjectives were the responses. Positive intersensory transfer, characterized by symmetry across modalities was obtained. The contribution of nonspecific learning to this effect was negligible. Intersensory transfer was found to be less efficient than the empirically determined maximum level of intrasensory transfer possible in this task.

Scale-model charge-transfer technique for measuring enhancement factors

NASA Technical Reports Server (NTRS)

Kositsky, J.; Nanevicz, J. E.

1991-01-01

Determination of aircraft electric field enhancement factors is crucial when using airborne field mill (ABFM) systems to accurately measure electric fields aloft. SRI used the scale model charge transfer technique to determine enhancement factors of several canonical shapes and a scale model Learjet 36A. The measured values for the canonical shapes agreed with known analytic solutions within about 6 percent. The laboratory determined enhancement factors for the aircraft were compared with those derived from in-flight data gathered by a Learjet 36A outfitted with eight field mills. The values agreed to within experimental error (approx. 15 percent).

Numerical investigation of heat transfer and friction factor characteristics in a circular tube fitted with V-cut twisted tape inserts.

PubMed

Salman, Sami D; Kadhum, Abdul Amir H; Takriff, Mohd S; Mohamad, Abu Bakar

2013-01-01

Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio (y = 2.93) and different cut depths (w = 0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Classical twisted tape (CTT) with different twist ratios (y = 2.93, 3.91, 4.89) were also studied for comparison. The results show that the enhancement of heat transfer rate induced by the classical and V-cut twisted tape inserts increases with the Reynolds number and decreases with twist ratio. The results also revealed that the V-cut twisted tape with twist ratio y = 2.93 and cut depth w = 0.5 cm offered higher heat transfer rate with significant increases in friction factor than other tapes. In addition the results of V-cut twist tape compared with experimental and simulated data of right-left helical tape inserts (RLT), it is found that the V-cut twist tape offered better thermal contact between the surface and the fluid which ultimately leads to a high heat transfer coefficient. Consequently, 107% of maximum heat transfer was obtained by using this configuration.

Numerical Investigation of Heat Transfer and Friction Factor Characteristics in a Circular Tube Fitted with V-Cut Twisted Tape Inserts

PubMed Central

Salman, Sami D.; Kadhum, Abdul Amir H.; Takriff, Mohd S.; Mohamad, Abu Bakar

2013-01-01

Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio (y = 2.93) and different cut depths (w = 0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Classical twisted tape (CTT) with different twist ratios (y = 2.93, 3.91, 4.89) were also studied for comparison. The results show that the enhancement of heat transfer rate induced by the classical and V-cut twisted tape inserts increases with the Reynolds number and decreases with twist ratio. The results also revealed that the V-cut twisted tape with twist ratio y = 2.93 and cut depth w = 0.5 cm offered higher heat transfer rate with significant increases in friction factor than other tapes. In addition the results of V-cut twist tape compared with experimental and simulated data of right-left helical tape inserts (RLT), it is found that the V-cut twist tape offered better thermal contact between the surface and the fluid which ultimately leads to a high heat transfer coefficient. Consequently, 107% of maximum heat transfer was obtained by using this configuration. PMID:24078795

Nurse-surgeon object transfer: video analysis of communication and situation awareness in the operating theatre.

PubMed

Korkiakangas, Terhi; Weldon, Sharon-Marie; Bezemer, Jeff; Kneebone, Roger

2014-09-01

One of the most central collaborative tasks during surgical operations is the passing of objects, including instruments. Little is known about how nurses and surgeons achieve this. The aim of the present study was to explore what factors affect this routine-like task, resulting in fast or slow transfer of objects. A qualitative video study, informed by an observational ethnographic approach, was conducted in a major teaching hospital in the UK. A total of 20 general surgical operations were observed. In total, approximately 68 h of video data have been reviewed. A subsample of 225 min has been analysed in detail using interactional video-analysis developed within the social sciences. Two factors affecting object transfer were observed: (1) relative instrument trolley position and (2) alignment. The scrub nurse's instrument trolley position (close to vs. further back from the surgeon) and alignment (gaze direction) impacts on the communication with the surgeon, and consequently, on the speed of object transfer. When the scrub nurse was standing close to the surgeon, and "converged" to follow the surgeon's movements, the transfer occurred more seamlessly and faster (<1.0 s) than when the scrub nurse was standing further back from the surgeon and did not follow the surgeon's movements (>1.0 s). The smoothness of object transfer can be improved by adjusting the scrub nurse's instrument trolley position, enabling a better monitoring of surgeon's bodily conduct and affording early orientation (awareness) to an upcoming request (changing situation). Object transfer is facilitated by the surgeon's embodied practices, which can elicit the nurse's attention to the request and, as a response, maximise a faster object transfer. A simple intervention to highlight the significance of these factors could improve communication in the operating theatre. Copyright © 2014 Elsevier Ltd. All rights reserved.

Selected natural and fallout radionuclides in plant foods around the Kudankulam Nuclear Power Project, India.

PubMed

Ross, E Mahiban; Raj, Y Lenin; Wesley, S Godwin; Rajan, M P

2013-01-01

The activity concentrations of certain radionuclides were quantified in some plant foods cultivated around Kudankulam, where a mega-nuclear power plant is being established. The activity concentrations were found more in the 'pulses' group and were the lowest in 'other vegetable' category. The annual effective dose was computed based on the activity concentration of radionuclides and it was found to be higher due to the consumption of cereals and pulses. Other vegetables, cereals, pulses and nuts recorded high transfer factors for the radionuclide (228)Ra. Fruits, leafy vegetables, tubers and roots, and palm embryo registered high transfer factors for (226)Ra. Group-wise activity concentration, radiation dose to the public and soil-plant-to-transfer factor are discussed in detail. Copyright © 2012 Elsevier Ltd. All rights reserved.