| The purpose of this study was to test the cytokine-inducing substance (CIS) permeability of a new kind of dialyzer-Syntra 160 in vitro dialysis with whole human donor blood. The dialyzers used in these tests were high-flux polyethersulfone dialyzers having an asymmetric membrane with a decreasing mean pore size distribution in an outward radial direction of support layer. Bicarbonate dialysate (D) was contaminated by Pseudomonas. aeruginosa (P.A) culture filtrate, and cytokine production in the peripheral blood mononuclear cells (PBMC) expressed as pg/2.5xl06 was used as the indicator of transmembrane passage of CIS. The experiments contain 2 parts. First part was to investigate whether the CIS can pass through the dialysis membrane to the blood side under several conditions, including D contaminated with different dilution of bacterial culture filtrate (10~2, lOMO-4) and different dialysis condition (no backfiltration( BF ), the net ultrafiltration = 0 , net BF = 10ml/min). Second part is to investigate its potential mechanism. The contaminated D (CD) was pumped from a reservoir to the D department of a dialyzer in a dead-end mode (arterial blood port closed). After 60 min of BF at a rate of 10 (part A) or 250 (part B) ml/min, permeate (from the venous blood line) and effluent D samples were obtained. In part B, a closed-loop system in which both the effluent D and permeate were recycles back to the D was used. Results:The total production of all IL-1a, TNF-a , IL6 were not detectable in the PBMC sample harvested from blood before exposure to dialyzer (BO), after 15 min circulating the whole blood with uncontaminated bicarbonate D (B15), 60 min after circulating the CD with 10-2, IQ-3,10-4 diluted bacterial culture filtrate (B60) and 60 min after the both blood and contaminated D keeping in still condition (B60S). While the IL-1cc, TNF-a, IL6 production in the 10-2, 10-3,10-4 diluted bacterial culture filtrate CD (CDO), the IL-1a production were 296.2?0.1, 260.6?56.7, 164.5?4.9, the TNF-a production were 477.0?60.7, 318.9?9.3, 102.6?7.0, IL6 production were 990.3?6.8, 750.3?86.9, 503.1+294.5 respectively. The IL-1Ra production in the group of D contaminated by 10-2 diluted bacterial culture filtrate was 156.8?1.6 in BO, 188.9?08.8 in B15, 271.2?127.4 in B60, 265.6?160.6 in BS60, 2971.8?123.0 in DO. In the group of D contaminated by 10'3 diluted bacterial culture filtrate, the IL-1Ra in BO, B15, B60, BS60, DO was 201.21154., 143.9?2.7, 208.7?9.7, 82.1?9.1, 2274.0?25.9. In the group of D contaminated with 10-4 diluted bacterial culture filtrate, the IL-1Ra value in BO, B15, B60, BS60, DO value was 116.3?0.5 , 127.8?0.8 , 111.7?8.5 , 107.0?6.1, 1175.5?03.0. There was no significant difference among the blood sample among B15, B60 and BS60, but the cytokine production in DO was much higher than any other group, the difference was significant. The same results also get in the situation of positive BF. In part A of the second part experiment,CD-associated IL-lp and TNF-a were 171.4?4.5 and 283.8?4.1, respectively, but undetectable in the permeating backfiltrate. In part B, cytokine production was again undetectable in the permeate. CIS adsorption was suggested by a significant D reservoir" mass balance error" (t=0 VS t=60 min) for both IL-10 (179.1133.7 VS 8.4?.6) and TNF (342.01114 VS undetectable).Conclusion: The Syntra 160 can effectively prevent the passage of cytokine-inducing substance from highly contaminated D under very critical condition. The potential mechanism is the absorption of these CIS by the polyethersulfone membrane.Second part: The influence of the dialysate flow rate,blood flow rate and temperature on hollow fiber masstransfer area coefficient and its potential mechanism( Abstract)The purpose of this study was to measure, in commercially available hemodialyzers, the spatial variation of the mass transfer area coefficient (KoA) for urea and to evaluate its dependence on dialysate flow rate (Qd), blood flow rate (Qb) and temperature (T).
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