The kinetics of coagulation factors and platelet factors during hemodialysis with different dialysis membrane materials and anticoagulants was investigated. The anticoagulants used for this study inclued heparin, low molecular weight heparin (LMWH), and nafamostat mesilate (NM). The membrane materials were Cuprophan, EVAL, PMMA and Hemophan. For EVAL membrane dialyzer, non-anticoagulant hemodialysis was conducted as a control, same kinetics with different anticoagulants was investigated. Heparin slightly suppressed the activity of factors XII and XI while LMWH suppressed the activity of the factor VIII. NM inhibited the solid phase reaction and the activity of factor VIII, and showed a clear suppressive effect on platelet activity compared with both types of heparin. Conceming the membrane materials, there were differences found in the activities of factor VIII, anti-factor X a and platelet factor-4 especially when heparin or LMWH was used an anticoagulant. We suspect that both types of heparin adsorption to Hemoplan and high thrombogenicity of PMMA probably reflected the antithrombotic effect in hemodialysis. Anticoagulants must be used considering the characteristics of membrane materials.

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Anticoagulant activity of FUT has been reported to be eliminated during hemodialysis (HD) with AN69 dialyser (PAN membrane, HOSPAL). This disadvantage was speculated to be due to adsorption of EDT by AN69. We compared the adsorption and anticoagulant activity of FUT between AN69 and DX (PAN membrane, ASAHI MEDICAL), which contains carboxyl group in contrast to sulfonate group in AN69, in vitro and in HD patients. Saline including FUT (40mg/l) was poured into mini-module(100cm²) of AN69 and DX at a rate of 2ml/min, and the concentrations of FUT at the outlet of these modules were measured. During HD with FUT(20mg/l of FUT was included in saline at the priming, and infused at a rate of 40mg/hr), EDT, amidinonaphthol (AN) and paraguanidinobenzoic acid (PGBA) which are resolved metabolites of EDT by plasma esterase activity, were determined in plasma entering and leaving these dialysers, and in dialysates. As results in vitro, more than 75% of FUT was adsorbed by AN69 during 3 hrs, although DX was saturated with FUT within 30min, FUT, AN and PGBA concentrations in plasma and dialysate at any point during HD were significantly higher than those with AN69. The number of fibers with clotted filaments reached more than 3% in AN69 dialyser, although no clotted filament was observed in DX. In conclusion, a large part of infused FUT was adsorped and isolated from plasma, and its anticoagulant activity was eliminated in HD with AN69, but not in HD with DX. This fault of AN69 was suspected to be due to combination of its sulfonate group and FUT.

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In order to clarify the effect of a newly developed PEG grafted cellulose membrane dialyzer (PEG) on coagulation-fibrinolysis and endothelial cell stimulation, a controlled cross-over study was done concering the increased ratio during HD in plasma thrombin-ATIII complex (TAT), fibrinopeptide A (FPA), FOP (D-dimer), alpha 2-PI-plasmin complex (PIC), tissue plasminogen activator (t-PA) and von Willebrand factor (vWF)(a marker of stimulation to endothelial cells) comparing PEG with dialyzers of three other membranes, i. e., regenerated cellulose(OC), PMMA (P), and cellulose diacetate (CD). TAT increased during HD but the increment was significantly lower in PEG than in OC. Both FPA and FDP (D-dieter) increased during HD and the increments were similar in the four different membranes. PIC significantly increased during HD in all four membrane but the increment of PIC was significantly less in PEG than in three other membranes (DC, P, CD). Changes in t-PA during HD were similar to those in PIC, vWF significantly increased during HD but increasd to a significantly less extent in PEG than in OC, P and CD. These results indicate that PEG shows less enhancements in coagulation-fibrinolysis and endothelial stimulation during HD than the others, suggesting that PEG may attenuate the recurrent damage to endothelial cells during HD.

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Continuous hemodialysis (CHD) is accepted as alternative method for conventional hemodialysis for treating acute renal failure in patients with multiple organ failure associated with unstable hemodynamics. Plasma levels of fibrinopeptide A (FPA), fibrinopeptide Bβ_15-42 (FPB β_15-42), thrombin/anti-thrombin III complex (TAT) and FDP-D-dimer were determined in 6 patients with hypercoagulative and fibrinolytic disorders during CHD. Nafamostat mesilate was administered for anticoagulation at 10-20mg/hr. These values of parameters descrived in the above decreased at 6 or 12 hours after the start of CHD, at 24 hours, regained to high initial levels. The FPA/FPB β_15-42 ratios obtained after 12 hours suggested an activation of coagulation system. In these instances, it is reasonable to assume that coagulation was stimulated in patients at 24 hours after the start of CHD. These results indicate that the mesurements of these parameters are useful to the timely exchange of hemodialyser and to the determination of the amount of anticoagulants.

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HIH is a serious complication in patients with maintenance HD therapy. We reported that DOPS, a synthetic precursor amino acid of norepinephrine (NE), was effective not only for HIH during HD but also for orthostatic hypotension and fatigue after HD. DOPS and it s metabolites were known to be excreted in urine. So, in this study, we evaluate the pharmacokinetics of oral dose of DOPS in the ex erimental rat with renal failure and in the patients with maintenance HD. As results from the study in the rats with ¹⁴C-DOPS, POPS metabolism was shown to be essentially unchanged in uremia, and DOPS did not accumulate in uremic rat. In patients suffering HIH with three times/week regular HD (4hrs), 300mg of DOPS was administered orally 1hr before the initiation of HD. Plasma DOPS concentration gradually increased during till, and reached a peak after 6hrs (1hr after HD) of the dose. It disappeared 24 hrs later. Plasma NE levels with DOPS were significantly higher than those without DOPS during 24 hrs, and highest (1.05±0.22ng/ml) after 6 hrs of the administration of POPS. The high level of NE was speculated to be contribute for the improvement of HIH and some complaints during and after HD. In long-term treatment with DOPS, plasma DOPS were not detected before the next administration periods, and plasma NE levels did not reachd to the unphysiological concentration in any patients. In conclusion, the safety and the efficacy of oral DOPS therapy for HIH were also supported by this pharmacokinetic study.

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We estimated the effects of long-term erythropoietin (EPO) administration to hemodialysis patients (HD Pts) on endothelial cell injury. Thirty HD Pts were administered EPO for 12 weeks. Hematocrit increased from 6.4 to 9.5g/dl. Blood pressure did not change. Plasma Endothelin decreased from 24.9±8.6pg/ml to 14.7±3.4pg/ml. ANP, ALD, PRA, ATII, and ADH did not change. Protein C and S significantly decreased at 4 weeks. We conclude that EPO did not abbreviate endothelial cell injury.

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To clarify the influence on the clinical efficacy of recombinant human erythropoietin (EPO) by the types of hemodialysis membranes, we made a retrospective study as well as a cross-over study utilizing two types of dialyzers. One is a conventional cuprammonium rayon membrane (CCM: low flux) and the others are various types of high flux hemodialysis membranes (HPM). The CCM-treated group consisted of 26 patients (male; 13, female; 13) and HPM-treated group consisted of 23 patients (male; 12, female; 11) respectively. There were no significant differences between two groups in the values of hematocrit (Ht) before treatment of EPO (CCM vs HPM, 20.0±2.0%, 18.9±1.6%), Ht after treatment of EPO (28.3±2.0%, 29.2±1.7%), the dose of EPO (4673±2053U/week, 4304±1613U/week) and the dose of EPO divided by dry weight (104±53U/week/kg, 85±31U/week/kg) respectively. Meanwhile, statistically significant differences were observed between two groups in various parameters such as the rate of increase in hematocrit (ΔHt) (8.3±2.7%, 10.3±2.3%, p<0.01) and the dose of EPO divided by ΔHt (13.4±7.6U/week/kg/%, 8.8±3.9U/week/kg/%, p<0.02). The cross-overstudy over 9 weeks period by two different membranes revealed that the clinical effect of EPO was enhanced significantly by the change from CCM to HPM (27.6±2.7% to 30.3±%, p<0.01). On the contrary, the change from HPM to CCM diminished the effect of EPO (29.1±1.5% to 28.6±1.3%). Since the serum concentration of EPO was same between CCM and HPM groups, the removal of EPO by HPM might be very small. These results demonstrate that hemodialysis using high flux membrane is benefical and has a sparing effect on the dosage of EPO.

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Solute permeability is available using Wilson-Plot Method, Klein's Method, RI Method with radioisotope-labeled solute and a new method with optical fibers. Each method gives different values for solute permeability of same membranes, and little is known real values for solute permeability. This paper describes characteristics of methods of measuring solute permeability, and effects of membrane structure on solute permeability of highly permeable (HP) dialysis membranes.
Real values for solute permeability of hollow-fiber dialysis membranes can be measured by a new method with optical fibers. Structural parameters of pore radius, surface porosity and tortuosity were determined for HP membranes from pure water permeability, solute permeability and water content data using the tortuous pore model. PAN-DX membrane has higher solute permeability than AM-EP membrane for substances of molecular weight ranging from 6, 000 to 20, 000, because PAN-DX membrane has huge pores.

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Binding of drugs to serum protein is an adsorption phenomena. Adsorption equilibrium and velocity of drugs influence their dialysance. We measured adsorption equilibrium and velocity with four cephem antibiotics and human serum albumin. CAZ, CDZM and CTRX had the adsorption isotherms that were obedient to Langmuir equation, but CTX did not. The difference of adsorption mechanism caused this difference. Protein-binding ratio changed with whole concentration of antibiotics, and they depended on antibiotics. The order of adsorption velocity was CDZM or CTRX, CTX and CAZ. Desorption amount of CAZ can be ignored while blood runs in a dialyzer, that of CTX cannot. Adsorption equilibrium of CDZM and CTRX forms anywhere in a dialyzer. It is important to examine the effect of adsorption equilibrium and velocity of drugs on their dialysance. We designed a mass transfer model of protein-binding drugs in a dialyzer. Based on this model, we calculated distribution of antibiotics concentration in a dialyzer. Distribution of free drug concentration and adsorption amount was dependent on their adsorption velocity, that of the whole concentration in blood side were not.

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Relationship between mass transfer and flow patttern in dialyzers is very important for optimal design of dialyzers. Mass transfer in dialysate-side is extremely complex to understand due to complexity of flow pattern. In this work, the basic analysis about mass transfer of dialysate was performed with single follow fiber membrane, which is considered as a simplest laminar flow condition. The experiment was carried out by the new method with optical fibers. The unsteady mass transfer model in a capillary membrane was applied to the new calculation method for the mass transfer coefficient of outside film of the hollow fiber membrane. AM-SD-10M which is conventional membrane and AM-FP-15 which is highly permeaole membrane were used in the experiment. No matter which membrane was concerned, mass transfer resistances of outside film were equal. Sherwood number measured experimentally fitted in with the Leveque's equation which was led by the theoretical analysis of heat transfer in laminar flow.

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To date no appropriate marker of dialysis arthropathy, mostly due to amyloidosis, has been identified. We investigated the usefulness of serum hyaluronic acid as a marker of dialysis arthropathy and the effects of regenerated cellulose membranes (RC) with large pores (CL-SS12W, Terumo, Tokyo) on dialysis arthropathy and serum hyaluronic acid. Among 54 patients receiving regular hemodialysis treatment (RHT), those with arthralgia, carpal tunnel syndrome, or carpal bone cysts had higher serum levels of hyaluronic acid than those without these complication. Serum hyaluronic acid levels correlated significantly with patient age, duration on RHT and serum aluminum levels. Differences in the effects on the arthritic symptoms and serum hyaluronic acid between large pore RC and conventional RC were examined in 10 patients with arthralgia receiving RHT. Only one out of 10 patients demonstrated an improvement in arthralgia with the use large pore RC. There was no change in serum hyaluronic acid levels. Serum hyaluronic acid decreased to the same extent during in both dialyzers. In conclusion, it is suggested that serum hyaluronic acid is a possible marker of dialysis arthropathy, probably amyloidosis and that large pore RC has only limited effects on dialysis arthropathy and serum hyaluronic acid.

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As a new dialysis system, continuous recirculation peritoneal dialysis(CRPD) was introduced in order to improve solute removal efficiency. In CRPD, patient's dialysate in peritoneal cavity was extracorporated through a double-lumen catheter and purified by an out-side dialyzer. From an canine ex vivo study, urea peritoneal and dialyzer dialy-sances were 3.05 and 33.3 ml/min under 100 and 200 ml/min of recirculation and dialysate flow rates using FB-50H(0.5 m²). From these results, weekly urea clearance was estimated as 115.51/week in 12 hr/day CRPD superior to 70.01/week of conven-tional CAPD and 99.81/week of 12 hr/week HD.

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For the treatment of CRF, extra-corporeal ultrafiltration method was used during cardiopulumonary bypass and continuous peritoneal dialysis (CPD) was performed postoperatively. The dialyzing . solution was continuously infused and drained. The duration of CPD ranged 7-19 days. The average of serum-potassium level did not increased during CPD. The average blood urea nitrogen and serum creatinine level increased mildley during CPD. The daily water removal by the CPD was 1284 ± 765ml/m². No complication attributable to the CPD was observed in any patients. We concluded that this metod was effective for treatmentof chronic renal failure following cardiopulumonary bypass surgery. And the CPD is more safety than hemodialysis because of the complication such as bleeding and hypotension.

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Adequate frequency of dialysate ex-change on APD was assessed by the kine-tic model for urea removal capacity. Maximum volume of dialysate infusion(MV)and in-traperitoneal pressure(IPP) were also studied in 7 adult and 4 pediatric patients. Maximum infusion volume on APDwas 2800 ml in patients with body weightof >60 kg, 2500 ml in patients of 50-60 Kg, 2100 ml in patients of 40-50 kg and 60 ml/kg in pediatric patients. An increment in IPP associated With increased dwelling volume was significantly lower in supine position than in upright and sitting position. Adequate frequency of exchange depended on the dwelling volume and peritoneal solute permeability, which was 5-6 times for patients with urea D/P(2 hrs) of 0.6 and 6-8 times for patients of 0.9. In conclusion, dwelling volume of 2000-2800 ml and frequency of exchange of 5-8 times seems to be adequate for adult patients on APD, which depended on the body fluid volume and peritoneal permeabi-lity.

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Four patients with acute renal failure, after cardiovascular surgery were treated with hemodialysis (HD). Circulatory instability during HD is a main problem. Therefore we measured SvO₂ continuously during HD as a predictor of change in cardiac output. In these of four patients, SvO₂ values was higher than 65% before HD, but SvO₂fell to less than 60% immediately after HD started. After 2 or 3 min-utes, hypotension was revealed. We conclude that in case of SvO₂ rapidly decreased immediately after HD started, or decreased less than 60% during HD, careful manage-ment of fluid balance or use of catecholamine is necessary.

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The object of present study is the development of a continuously monitoring sensor for ET concentration in dialysate. ET is readily capable of penetrating from dialysate into blood through highly permeable membranes. Dialysate should be kept ET free and should be observed absence of ET by continuous measurement. Limulus test is generally used for the measurement of ET concentration in clinical settings. Conventional operation of Limulus test needs complicated operation because of its sensitivity to contamination from atmosphere. Therefore conventional Limulus test is unsuitable for continuous ET measurement. The authors designed a new ET sensor operating the continuous reaction of Limulus test in single tube. This sensor enabled sample solution to react without contact with atmosphere and simplified continuous ET concentration measurement. The sensor showed faster response than conventional Limulus test and had measurable ET concentration range concluding allowable ET concentration limit. The developed ET sensor is promising for monitoring of ET in dialysate lines.

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We examined the clinical usefulness of the disinfectants in two respects, namely the corrosve effect on piping materials of dialysating machine, and dissolbility of calcium carbonate. The Disinfectants we examined were sodium hypochloride, QC-70(AMTEC), MC-1000(MEDICO CHEMIE), and SHUMMA(SASAKI KAGAKU). The materials we tested were stainless steel(SUS304 and SUS316), polypropylene, siiicone and teflon. Each material was cut to sive inner surface area of 20cm², and soaked for 28days in a solution of each disinfectant. To test their dissolubility, 0.5g of calcium carbonate was mixedwith 50ml each of the disinfectansand the aceticacid solution, as control. After stirring it well, each sample solution was collected and the ionized calcium level was measured. Both of the stainless steel were corroded by sodium hypochloride and SHUMMA. Polymer materials were not corroded by any of the disinfectants examined. None of the disinfectants could dissolve calucium carbonate. However acetic acid solution could dissolve the calcium carbonate of the concentration as higher than l%. We conclude four our study that polymer material is more preferable than stainless steel in terms of the corrosivity. Among the disinfectants we examined and the acetic acid, only the acetic acid can dissolve calcium carbonate with the as low as concentration 1%. Therefore, calcium carbonate deposite on the innersurface of the pipe could be removed by acetic acid solution.

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Blood components deposition on various membranes including cellulose (OC), new PEG grafted cellulose (PC), cellulose diacetate (CDA) and polymethyl methacrylate(PMMA) were investigated after hemodialysis. The amount of adsorbed proteins were the most prominent in PMMA (10.38 ±1.67μg/cm²), while CDA 0.495±1.27, μ/cm²), and PC (6.50±2.61μg/cm²) were small. The amount of adsorbed LDH were the smallest in PC (3.33±3.05×10_-4U/cm²) and the largest in PMMA (49.36±17.53×10_-4U/cm²). Analysis of adsorbed protein by SHE-PAGE method showed different among the membranes. The band of high moleculer weight was small and that of alubumin was large in PC compared with CDA and P4 A. PC had the least blood components deposition among four membranes detected by scanning electron microscopy. It is considered that these results may contribute to the anti-thrombogenicity on PC membrane.

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The tap water was highly purified by reverse osmosis system, and the bicarbonate reservoir was cleaned and disinfected every day. Then, the cleaned dialysis fluid was moreover purified through the double ultrafiltration(UF) filters with 6, 000 dalton cut off point. The finally obtained dialysis fluid could exceed the authorized critical standard for the infusion fluid of the clinical use. This ultrapure dialysis fluid did not clinically increase the plasma endotoxin(ET)(4.1±1.8pg/ml, 1.8±0.9pg/ml), interleukin-1β(IL-1β)(9.3±5.1pg/ml, 9.3±4.9pg/ml) and serum amyloid protein-A (SAA)(12.9±4.2μg/ml, 9.8±5.3μg/ml)after the hemodialysis using the polysulfone dialyzer. Furthermore, this ultrapure dialysis fluid was infused for the substitution fluid through the additional double UF filter as the on-line hemodiafilt-ration(on-line HDF). Our clinical on-line HDF trial did not also introduce the rise in ET(3.1±1.9pg/ml, 2.3±1.1pg/ml), IL-1β(11.0±6.7pg/ml, 8.3±15.6pg/ml) and SAA(10.8±4.8μg/ml, 7.9±4.3μg/ml). Our data showed that the ultimate purification of the dialysis fluid was achi-eved by the present methods. In conclusion, the ultrapure dialysis fluid was able to be in-fused safely in the on-line HDF.

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As the hemodynamics become unstable in post-operative acute renal failure patients, it is necessary to prevent hypotension during blood purification. Using a Swan-Ganz catheter we studied the hemodynamics of acute renal failure patients following surgery during hemodialysis (HD) and continuous hemofiltration (CHF). The hemodyanamics were measured 110times. The results were as follows: 1) HD using the V-V method was more stable than HD using the A-V method and CHF was more stable than HD using the V-V method from the hemodynamic view point. 2) The patients who exhibited hypotension had decreased cardiac function due to hypovolernia or cardiac failure. 3) Most of those had simultaneously decreased total vascular resistance. 4) It was necessary to prevent hypotension during blood purification by avoiding ultrafiltration-induced hypo-volemia and using inotropic agents. 5) CHF was safer and more useful than HD in the hemodynamics.

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Four stable patients undergoing maintenance hemodialysis at Shinseikai Daiichi hospital and kawashima hospital were studied. A 4-hours hemodialysis was followed by 6-day hemofiltration was performed. Heparin was continuously infused at the rate of 500 units/hour. Three liter replacement solution was infused at the venous side, and 5 liters of ultrafiltrate was obtained daily. Hemofiltration system including heparin infusion pump, filter and circuit weighed 1.2kg. Patients wearing the entire unit could move about freely. The blood pressure of patients remained stable and hypotension episodes didn't occur during CAVH. No changes in hemoglobin and hematcrit level were observed in any patients. BUN levels were 25.6±15.7mg/dl and 93.6±9.8 mg/dl, immediately after HD and 6-day later, respectively. Creatinine level was 4.16±2.20mg/dl im-mediately after HD and reached to 10.86±0.58mg/dl. 6 day later. PH was 7.464 im-mediately after HD reached to 7.387 6 day later. Base excess was 3.18mEq/L im-mediately after HD and reached 4.16.mEq/L at 6 day later, HCO3 was changed from 25.O4±3.52mEq/L immediately after HD and reached to 19.04±2.0mEq/L, at 6 day later. Serum calcium level varied from 4.0-5.5mEq/L. Serum phosphate increased to more than 6.0mg/dl in one patient. Serum β2-microglobulin level decreased during 1-2 week CAVH.

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Critically ill patients in the intensive care unit often cannot tolerate conventional hemodialysis because of their hemodynamic instability. Continuous hemofiltration (CHF) and continuous hemodialysis (CHD) have become widely used as renal replacement therapy for critically ill patients with acute renal failure. We report the outcome of 48 patients who were treated with CHF or CHD compared to that of 30 patients treated with hemodialysis or peritoneal dialysis. The overall mortality was not significantly different between two groups (41.6% vs 40.0%), however it was apparent that CHF and CHD treatment were effective on severer patients. Mean creatinine clearance (MCCr) of CHD was 12.1ml/min, and was significantly higher than that of CHF. Adequate fluid removal was also achieved during CHD as well as during CHF. Therefore, we conclude CHD is superior to CHF for the critically ill patients with acute renal failure.

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The effect of the filter design on in vitro pressure drop and the performance of three different types of polyacrylonitrile (PAN) CAVH filters were studied. Two effects of the filter design were examined. (1) the length of hollow fibers in the housing, (2) the diameter of hollow fibers in the housing, were examined. The lowest pressure drop (13mmHg at Q_B=50ml/min) was obtained with the type C filter which is of a short length and wide diameter hollow fiber. High UFR (Q_F=17ml/min.) was obtained at a low pressure drop(30mmHg) with the type C filter. A good compatability of Q_F between experimental data and theoretical hypothesis using the gel-polarization model was obtained at low Q_B and high THP.

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Membrane charge was studied by staining method using cationic dye (methylene blue;MB) and anionic dye (orange II;OR) in 6 different dialysis membranes, taht is, plyacrylonitrile (AN69), polymethylmethacrylate (B2 and BK), polysulfone (PS), regenerated cellulose (RC) and hemophan(HE)membrane. AN69 and B2, which have negatively charged portion as sulfon group in the polymer, were stained by MB. HE, which has positively charged portion as third grade amine group in the membrane component, was stained by OR. Other PS, BK and RC membranes were not strongly stained by MB nor OR. These results suggest that evaluation of membrane charge using cationic and anionic dye is useful.

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The amount of dialysis membrane charge affects electrolyte transport through membrane. But its exact charge has not been measured directly. The authors tried to use fluorescence method which is used for biomembrane potential measurement in order to measure hollow-fiber dialysis membrane charge. An intensity of anionic fluorescent dye;1-anilinonaphthalene-8-solfonic acid(ANS);increases when it binds to charged parts of hydrophobic substances. Measurement of fluorescent intensity was made with two kinds of hollow-fiber dialysis membranes of regenerated cellulose;negative charged RC and positive charged Hemophan. Little fluorescence detected with RC indicates no ionic bond between ANS and negative charged membrane. In case of Hemophan, extremely intensive fluorescent was observed, but fluorescent intensity was decreasing with a decrease of membrane charge. A fluorescent intensity of ANS is considered to reflect hollow-fiber membrane charge. Moreover, fluorescent intensity corresponds to the quantity of bound ANS in dialysis membrane. This may also make it possible to analyze dialysis membrane structure.

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Electrolyte transport depends on the effective charge density of charged dialysis membranes, and hence determination of effective charge density i s needed to determine inorganic phosphate permeability. However, great difficulty i n measurement of membrane potential of hollow-fiber dialysis membranes makes it impossible to quantitatively compare effective charge density with diffusive permeability for inorganic phosphate. We prepared sheet membranes (16μm thick) of the same material as that of hollog-fiber RC (Regenerated Cellulose) and Hemophan membranes to measure membrane potential from which effective charge density was calculated. Zeta potential of each hollow-fiber membrane was determi nened by the streaming potential method. Diffusive permeability of hollow-fiber RC and Hemophan membranes was also measured with inorganic phosphate in purified water and in saline. Hemophan membrane has higher diffusive permeability than Regenerated Cellulose (RC) membrane, and its value i n saline i s higher than that i n purified water when the absolute value of effective charge density of positively charged Hemophan membrane i s comparable to that of negatively charged RC membrane. Zeta potential of each membrane is negative, and the absolute value of zeta potential of Hemophan membrane is smaller than that of RC membrane. Hemophan membrane has the same internal structure as RC membrane. This indicates that electrostatic resistance may control inorganic phosphate permeability. In conclusion, charge density affects inorganic phosphate transport through charged dialysis membranes that is enhanced by positively charged Hemophan membrane. Inorganic phosphate transport through dialysis membranes may be evaluated by the measurement of zeta potential of hollow-fiber membranes.

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Recently, dialysates with sodium acetate (D-A·Na) has been changed for dialysates with sodium bicarbonate (D-B·Na). In long term hemodialysis patients, hypertension often relaps after changing D-A·a with D-B·Na. Uncontrolled hypertension is also often accompanied by patients who are administered erythropoietin. Although D-A·Na is superior to D-B·Na for the therapy of hypertension in these patients, some cases manifest severe hypotension during HD using D-A·Na. Therefore, we investigated a new system which mix D-A·Na and D-B·Na. Mixing ratios of two dialysates are six kinds. This system was applied for 5 patients. Hypertension in the period of using D-B·Na and hypotension during HD using D-A·Na were all improved in all the patients.

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Composition uniformity and formula reproducibility of the dry type granu-lated dialysate, AKDD, Town Pharm., were evaluated, in comparison with those of the control, AF-2, a liquid type dialysate concentrate. Both of these dialysates are of glucose-added bicarbonate type. Samples were taken according to a statistical experimental nested design. Three bags were extracted from each of three lots (3×3) and five 1.0 gram samples were randomly taken from each of bags: 45 samples were used in total for this study. Na and K were determined by the flame photometry, Ca by the OCPC method, Mg by the xylidyl-blue method and the flame atomic absorption spectrometry and glucose by the enzyme method respectively, The results confi-rmed the uniformity of all observed components of AKDD with less than 2.0% of C.V.s (coefficient of variance), which were equivalent to those obtained with AF-2. The result also conformed to the uniformity test standard of the Japanese Pharmacopoeia XI. Error in the formulation reproducibility was 0.6% for Na, 3.5% for K, 4.7% for Ca, 1.3% for Mg and 1.6% for glucose respe-ctively.

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An advent of a high performance dialyzer, which can effectively remove β₂-microglobulin related to dialysis amyloidosis, brings a new issue in contamination of endotoxin through the membrane by back filtration and necessitates more sterile dialysate. We developed a new central dialysate delivery machine exclusively designed for glucose-added bicarbonate-buffered dry chemical (AKDD: Towa Pharm.) and evaluated it clinically for 2 weeks. The machine, which was operated for the total period of 216 hrs, produced amounts of dialysate as required at any time. The mean dialysate concentration during the whole period was Na 141±1.5 mEq/l, K 1.97±0.04 mEq/l, HC0₃^-23.9±1.04mEq/l, Ca 2.70±0.03mEq/l, and Mg 1.10±0.01mEq/l. Dialysate endotoxin level varied from 0.74±1.01 pg/ml, at the start of operation to 1.41±2.01pg/ml(n=11) 6 hrs later. These results suggested that the machine can produce a dialysate with more consistent concentration and higher sterility grade from the dry chemical(AKDD). The package of the dry chemical had advantages to save working time and physical power for personnel.

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The Wearable artifieial kidney using veno-venous (V-V) blood access consioto of four parts: d-FDL catheter (flexible double lumen catheter with Dacron cuff); hemofilter made of polyacrylonitrile (0.1m²); small blood pump (1.2kg); and circuit and safety devices. The d-FDL catheter was inserted through the subclavian vein by Seldingers' method. A Dacron cuff is used to prevent infection via the skin.Heparin was continuously injected into the circuit using a micropump (200 g). Two pumps are operated by a charging battery. This system was applied for 5 HD patients. Continuous veno-venous hemofiltration was performed for 24 hours in 2 patients. Hypotension was not observed in either case. Three advantages were recognized in this system compared with the previous one using an arteriovenous (A-V) fistula.

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The recent devised hemodialysis machines are usually equipped with ultrafiltration controllers to facilitate the use of high-flux dialyzers, and they are greatly contributed to blood purification therapy. However, the number of components has increased, which has led to complications in the systems. It has been attemped that the system has now been simplified by reducing the number of components without spoiling the high-accuracy of ultrafiltration control, even then the high-flux dialyzer is used. The new ultrafiltration control system has only one third the working parts of the conventional system, and trouble-prone parts(pump, electromagnetic valve, etc.) have been reduced by half also. The system's basic operation is the transmembrane pressure(TMP) control. The TMP is measured on the dialysate flowing state, not during ECUM, which makes possible to gain the high-accuracy ultrafiltration. In vivo, the high-accuracy ultrafiltration controls (-73.6±101g(N=45) for 3448±747g average ultrafiltration volume) was obtained using of the high-flux dialyzer.

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Highly permeable (HP) membranes have higher solute permeabilities than conventional ones. Contribution of blood- and dialysate-side mass transfer resistances to solute removal performance is more increased in HP dialyzers than conventional ones. To reduce blood- and dialysate-side mass transfer resistances effectively increases solute removal performance especially of HP dialyzers. This paper describes the technical design of dialyzers with being reduced blood-side mass transfer resistance. Dialyzers consisting of hollow-fiber membranes of 19.4cm in length was superior in solute removal perormance to dialyzers consisting of hollow-fiber membranes of 23.5cm in length. Overall mass transfer coefficient and blood-side mass transfer coefficient were independent of blood-side flow rate. Overall mass transfer coefficient was independent of inner diameter of hollow fibers.

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Effects of hemodialysate and plasma of 11 patients with chronic renal failure (CRF) on lymphocyte blastogenesis was examined. Of 11 hemodialysate 10 enhanced [³H]thymidine incorporation into mitogen-stimulated healthy lympocytes. Plasma of these patients before dialysis significantly enhanced lympocyte blastogenesis when compared to healthy plasma (n=10), whereas the activity of plasma after dialysis did not differ significantly from that of healthy plasma. The experimental hemodialysate of CRF blood significantly enhanced lymphocyte blastogenesis, when compared to that of healthy blood. Healthy or CRF plasma was filtrated by a membrane with a molecular cut off of 3, 000 daltons. The filtrate of CRF plasma significantly enhanced blastogenesis, compared to that of healthy plasma. This activity did not abolish by heat tratment (100°C, 40min). Any drugs administered to the patients or creatinine did not enhance blastogenesis. These results suggest the presence of blastogenesis enhancing factor(s) in CRF hemodialysate.

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3-Carboxy-4-methyl-5-propyl-2-furanpropionic acid (CMPF) is accumulated markedly in uremic serum. To detemtine cell-toxicity of CMPF, its effect on mouse erythroid colony formation (CFU-E) and mitochondrial respiration was studied. Bone marrow cells obtained from mouse were cultured, and the effect of CMPF on CFU-E was studied. CMPF inhibited CFU-E significantly at a concentration of 200μg/ml. To determine the mechanism of cytotoxicity of CMPF, the effect of CMPF on respiration of mitochondria obtained from mouse liver was studied using oxygen electrode. CMPF inhibited mitochondrial state 3 respiration dose-dependently. The inhibition was also observed in the presence of serum albumin, and even at a concentration of 50μg/ml, which is comparable to the serum level of CMPF in uremic patients undergoing hemodialysis. These results indicate that CMPF is toxic to cells due to inhibition of energy (ATP) synthesis by inhibiting oxidative phosphorylation of mitochondria.

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Clinical evaluation was conducted for antithrombogenicity of three different HPMs (PAN: DX, PMMA: BK, and Cellulose: TF) with 6 patients. In SEM observation, more coagulations were observed with BK and TF than with DX. LDH, the index of blood cells adsorbed onto inner wall surface, was also higher with BK and TF. Blood residual ratio was lowest with DX. There was no significant difference among the three in the indices of thrombocyte activation (the number of platelets, β-TG and PF-4 values). In the indices of thrombosis (FPA and TAT values), the three showed a similar rising tendency during hemodialysis, but the tendency was most moderate with DX. As for D-dimer, the index of the secondory fibrinolysis, change during hemodialysis remained small with all of the three, without any reflections of the results of the SEM observation and the FPA and TAT values. Judging from the above results of evaluation, DX is considered most recommendable of the three HPMs.

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By combining a polyacrylonitrile (PAN)-polyethyleneoxide (PEO) membrane with ionically heparin-bound catheter, tubing, and module header, a totally antithrombogenic continuous ultrafiltration system (ACUS) was developed. Antithrombogenicity of PAN-PEO hollow fiber membrane was considered to be due to the presence of highly concentrated PEO near the inner surface of the membrane which has a finely dispersed microstructure. ACUS was clinically applied to 24 patients without systemic anticoagulation and one PAN-PEO filter functioned for average 32 hrs without deteriorating their bleeding tendencies.

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The effect of module design on in vitro clearance of highly permeable polyacrylonitrile (PAN) dialyzer was studied. This membrane (PAN DX) has large pores to have a good solute permeability. Type A is a conventional dialyzer in which the packing ratio of hollow fiber is 60%. Type B has higher packing ratio (66.5%), and the spacer filaments which are dispersed among hollow fibers in order to improve the uniformity of dialysate flow. X-ray CT method shows that dialysate flows more uniformly in type B dialyzer. Higher values in vitroβ₂-MG and dextran (Mw=10, 900 and 38, 000) clearance are obtained in the type B dialyzer than the type A dialyzer without the spacer filaments.

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We invented the dialyzer with gentle protuberance around the inlet of a hollow fiber membrane of which surface was smoothed. Observation of flow in blood port using a dye clarified that occurrence of vortex was inhibited and retention time of blood was about a half in our dialyzer header as compared with a conventional header. Extracorporeal circulation of mongrel dogs without heparin, using a conventional header became impossible by blood clotting after 45 minutes. On the contrary, pressure drop by the dialyzer with a new header was 114±33mmHg even after two hours of circuration. Moreover almost nochange of plat 1 et counts allowed us to confirm that the blood flow and antithrombogenecity were improved in this header.

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Improved regenerated cellulose (CL-SS) dialyzer, which has clinical effects on reducing or improving pruritus and shoulder joint pain, was studied on performance and membrane physical properties. In determination of sieving coefficient curve with dextran, CL-SS membrane was superior to original regenerated cellulose (CL-SU) membrane in solute permeability for high molecular weight. Backfiltration of CL-SS dialyzer calculated theoretically was much smaller than that of other HP dial-yzers (polysulfone and cellulose triacetate dialyzers) at lower ultrafiltration rate, where Backfiltration is likely occur. Experimentally determined backclearance of CL-SS dialyzer for myoglobin was smaller than that of other HP dialyzers. In physical properties investigation with bond water and membrane potential, CL-SS membrane had less hydroxy radical structure than CL-SU. These results demonstrated that CL-SS membrane has possibility of smaller stimulation to organism.

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The efficacy of polysulfone membrane dialyzers (PS) in removing β₂-MG and small molecular weight substances such as P, UN, creatinine from the bloods of long-term maintenance dialyzed patients was evaluated in comparison with those of cellurose and other artificial membrane dialyzers. The results were as follows (1) The removal rate and amount ofβ₂-MG by PS were significantly higher than those by control membrane dialyzers, 55.8±9.9% and 207±57.0mg, respectively. In addition the removal rate and amount of P by PS were also significantly higher than those by control membrane dialyzers, 65.2±8.6% and 768±70mg, respectively, although there were no differences among all dialyzers in removing UN and creatinine. There also was no detectable leakage of albumin by PS. (2) In 12 patients with high blood levels ofβ₂-MG, the long-term use of PS for 28 weeks reduced blood levels ofβ₂-MG from 40.9±3.2mg/l to 27.2±3.1mg/l, thereafter they remained around 30mg/l. The blood levels of small molecular weight substances were unchanged. These results clearly indicate that PS membrane dialyzers might be useful in the removal ofβ₂-MG for short periods of time.

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The modifiedd cellulose was developed by fixing the modification agent to inner surface of regenerated cellulose hollow fiber during spinnig process. The modification agent (fluorine polymer) was fixed on the cellulose surface by covalent bonding, and antioxidantα-tocopherol (vitamin E) was fixed by hydrophobic bonding. ESCA showed that 39.9% fluorine atomic number rate was fixed on the inner surface of regenerated cellulose. Biocompatibility of modified cellulose membrane was tested compared to the original cellulose membrane by in vitro and extracorporeal circulation in mongrel dog. The modified cellulose showed excellent antithrombogenesis, and little complement activation hemodialysis leukopenia.

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The superstructure of polymer alloys responsible for their functions is most readily controllable at varying polymers, polymer blend ratios, solvents and temperatures. Dialysis membranes made of polymer alloys may have various pure water and solute permeabilities, pore sizes and pore size distributions. Commercially available FLX-12GW dialyzers and three kinds of test dialyzers of varying coagulation rate of forming PEPA membranes were prepared. Filtration experiments were made with a mixed solution of dextrans ranging in their molecular weights from 3, 000 to 60, 000. Reflection coefficient of dextrans was determined by Spiegler-Kedem equation from real rejection data calculated from rejection data by the velocity variation method. Reflection coefficient of FLX-12GW increased with molecular weights ranging from 10, 000 to 50, 000 of substances. Coagulation rate of forming PEPA membrane decreases with reflection coefficient.

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In order to eliminate endotoxin(ET) from dialysate, microporous hollow fiber membrane composed of polyethylene(Sterapore DA; DA, Mitsubishi Rayon Co.Ltd.) was attached to dialysate outlet line just before dialyzer, and changes in ET removal capacity(endospacy method), pressure drop through DA and accuracy of ultrafiltration control of delivery machine were evaluated for 20 weeks. ET concentration in dialysate fluctuated from 13.6 to 48.1pg/ml before DA, however it was decreased below detection limit(1.0pg/ml)after passing through DA at any timepoint during the study. Pressure drop of dialysate attributable to the passage through DA was 10mmHg at 0week, then it increased to 69mmHg at 20weeks. Accuracy of ultrafiltration control evaluated in vitro at 0 and 20 weeks, showed no significant difference. From these findings, it is concluded that despite pressure drop increases in the long-term use, DA appears to be useful as ET elimination filter for dialysis therapy.

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To enable a high density culture of hepatocytes for use as a hybrid artificial liver support system or a bioreactor system, a packed-bed reactor using reticulated polyvinyl formal (PVF) resin was applied to the primary culture of hepatocytes. Cubic PVF resins (2×2×2mm³, mean pore size: 100, 250 or 500μm) were used as supporting substrates to immobilize hepatocytes. Two hundred and fifty PVF cubes were packed in a cylindrical column, and 2.6-11.3×10⁷hepatocytes were seeded in the reactor by pouring 3ml of medium containing hepatocytes. Perfusion culture experiments using this packed-bed reactor, as well as monolayer culture using conventional collagen-coated Petri dishes as control experiments, were performed. Sufficient amounts of hepatocytes were found to be entrapped in the reticulated structure of the PVF resins. The highest density of immobilized hepatocytes attained with PVF resin were 1.2×10⁷cells/cm³-PVF. Hepatocytes immobilized in the PVF resin showed a sufficient level of metabolism of ammonium removal and urea secretion comparable to those in the monolayer culture. It is concluded that the packed-bed reactor system using PVF resin is a promising process to develop a bioreactor or a bioartificial organ using hepatocytes.

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In order to develop hybrid artificial liver based on cultured hepatocytes, it is necessary to establish high cell-density culture system which has highly differentiated functions and longevity. We found that hepatocytes attached on PVLA ( poly-N-p-vinylbenzyl-D-lactonamide), a synthetic polymer of asialoglycoprotein model, remarkably formed multilayer aggregations which expressed highly differentiated functions and longevity. In this study, we attempted to culture adult rat hepatocytes on PVLA-coated hollow fibers in perfusion culture module. Hepatocytes attached on PVLA-coated hollow fibers in the module formed multilayer aggregations which was high cell-density. Hepatocytes in the multilayer aggregations on PVLA-coated hollow fibers exhibited a better maintenance of differentiated functions such as the secretion of albumin, ureogenesis and activity of ammonia removal than those in the monolayer culture on collagen-coated follow fibers. Hepatocyte culture system using PVLA-coated hollow fibers in perfusion culture module has useful advantages for the development of hybrid artificial liver.

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A prototype of the artificial liver system was designed to use a spherical multicellular aggregates of adult hepatocytes (spheroid) that substitute for insufficient metabolism during hepatic failure. The spheroid, about 100μm in diameter, were formed by assembling of hepatocytes in the pores of polyurethane foam (PUF/three dimensional culture). Highly differentiated hepatic functions were maintained in the spheroid. These spheroids partly attached and immobilized in the pores of PUF. Then, we have designed a PUF/spheroids packed-bed culture system. Albumin and urea production activities of hepatocyte/spheroid immobilized in the PUF packed-bed were higher than those of usual hepatocyte/monolayer culture in petri dish, and these activities were maintained during 26 days. These results indicated that PUF/spheroid packed-bed culture system provided a promising prototype of hybrid type artificial liver system.

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The achievement of high performance hepatoc tes are required, to establish a new type of hybrid artificial liver. Newly developed cellulose microcarriers are multiporous, and cells are cultured in the inside of the pores of microcarriers as well as on the surface of them. In this study, cellulose microcarriers were investigated of their usefulness for high density culture of hepatocytes. Positively charged cellulose microcarriers revealed the best cell attachment by fibronectin or collagen coating. Intermittent stirring appeared to be the optimal method to attach hepatocytes to microcarriers. The optimal concentration of type I collagen was 0.03% for the attachment of hepatocyte to the carriers, and fibronectin sowed relatively better cell attachment than collagen did on static dish culture method. Hepatocytes, attached on the surface and in the inside of the microcarriers, kept their round-shape and these findings were observed also after 14 days of incubation.

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We found that regulating of differentiation and proliferation of hepatocytes which were cultured on polystyrene dishes can be achieved by varying the amount of lactose-carrying styrene polymer (PVLA) coated on the dishes. The result of the experiment, 3H-thymidine up-take of cultured hepatocytes is the lowest for cells cultured on dishes coated with high amount of PVLA in which the hepatocytes are round and high bile acid release was observed. But the highest thymidine uptake was observed in dishes with low PVLA coating in which the hepatocytes are spread and low bile acid release was observed.

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For the final purpose of developing a module by immobilizing floating spheroids once formed on flat plates to inner surfaces of support materials, first, we have investigated culture conditions for selective formation of floating spheroids on surfaces coated with polylysine (PL), and effect of surface characteristics on stable re-attachment and expression of functions. Culture conditions which improve the initial spreading of the cells increased spheroid diameter, and had a retarding effect on the formation of foating spheroids, probably because these conditions aggregated more cells into one spheroid. The most rapid formation and floating of spheroids were observed in a medium supplemented with insulin and dexamethasone. The spheroids formed in this hormone condition on PL-coated square dishes (Nunc; 500 cm²) were collected by gentle pipetting on the 7th day, and were reseeded onto surfaces coated with various concentrations of PL and fibronectin (FN) solution.“Stably-attached”aggregates were obtained on surfaces coated with both PL and less than 5μg-FN/mL, and the ones coated with PL alone. These“stably-attached”spheroids secreted albumin for 2 weeks at a high level.

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