With various highly permeable dialysis membranes which were developed to remove Beta-2-microglobulin, pore size was obtained by both differential scanning calorimetry (DSC) and tortuous pore model studies, and pore diameter distribution was measured by the BET method. The pore size of dry membranes is lower than that of wet membranes. Both pore diameter and pore volume of highly permeable dialysis membranes are higher than those of conventional dialysis membranes. Pore diameter distribution of regenerated cellulose membranes is somewhat different from that of synthetic polymer membranes.

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Two different types of membranes made of the same material were developed and their solute permeation characteristics were examined. One is PAN CX₂ membrane which has double layer void structure, and the other is PAN DX membrane which has gradient micro porous structure. Both membranes showed the similar filtration characteristics: SC for β₂ M 0.6, SC for Alb 0.001-0.002 and no permeation of endotxin, which demonstrate the sharp cutoff characteristics.
On the other hand, the solute permeability (Pm) of the membranes gave the diffrent results. Higher values of Pm were obtained with PAN DX for all the solutes tested, e. g. Pm for β₂ M was 5.9×10^-5cm/sec with PAN DX, whereas 4.9×10^-5cm/sec with CX₂.

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Changes in clearances of hemofilters were studied during in vitro or in vivo hemodiafiltration(HDF) using 3 different membrane filters; AN69HF (Hospal), F60 (Fresenius), FB190U (Nipro). No changes in clearances of low molecular weight substances and ultrafiltration rates were observed in all 3 hemofilters. A mild serial decrease in beta-2-microglobulin(B2M) clearance was noticed with a concomitant decrease in its sieving coefficient in all 3 hemofilters. The decrease in B2M clearance seemed to be caused by a diminish in membrane pore size. This decrease seemed to be related to membrane pore size rather than membrane charateristics, because F60 and FB190U filters with a larger pore size had more prominent decreases in B2M clearance than AN69. Push/pull HDF did not ameliorate the decrease in B2M clearance.

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We examined the adsorptive characteristics of PAN and PMMA membranes for proteins. The membranes used for hemodyalysis were perfused with 8M ureic solution. And the perfusates were analyzed with two-dimensional electrophoresis(2-DE). In addition, removal proportion and sieving coeff cient (SC) of retinol-binding protein (RBP), lysozyme and β₂-microglobulin(β₂-MG) were examined in each membrane. High removal proportion and low SC of lysozyme suggested the strong adsorption in PAN membrane. 2-DE of PAN membrane perfusate showed many spots including β₂-MG, albumin (Alb) and transfferin(Tf)on polyacrylamide gel. PMMA membrane showed low SC of β₂-MG and RBP, which were recognized as spots on polyacrylamide gel as same as IgG and other proteins by 2-DE. These results showed the strong adsorption of β₂-MG and RBP in PMMA membrane. We concluded that adsorptive characteristics of PAN membrane were different from those of PMMA membrane for proteins.

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Low molecular proteins which should be eliminated from long term hemodialysis patients such as beta-2-microglobulin are difficult to remove through the dialysis membrane only by diffusion. Some membrans adsorp the proteins, though, there are no good methods to meaure its adsorption capacity. Therefore, we tried one of an easy way to measure and to compaire the membrane adsorption capacity. This method shows that polysulfon and PMMA-BK have high adsorption capacity to beta-2-microglobulin which pK is around 5. Although polysulfon also adsorps 1 ysozi me of pK 11, only few is adsorped on the PMMA-BK membrane. It is neccessary to measure the capacity with low and high pK proteins.

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In recent years, the so-called high-performance membranes have come to be widely used. Conjecturing that there occurs adsorption of drugs by the membrane due to the chemical properties of the membrane material or electrical potential, we measured the blood concentration as well as the adsorption of drugs in dialysis. patients. Regarding cefuzonam sodium, no adsorption by the membrane was observed after each membrane was used for a seven-hours recycle. Rifampicin was strongly adsorbed by the PMMA membranes (B1-1.OH, B2-1.OH, BK-1.OU), but not by the EVAL nor cellulose membrane. Aprindine hydrochloride was also adsorbed by the PMMA membranes. In dialysis sessions using the PMMA membranes, the same results were obtained regarding the measurement of blood concentration of these drugs. This led us to conclude that the adsorption of drugs depends to a large extent upon both the electric charges of the drugs and the membrane surface of the hollow fiber rather than the molecular weights of the drugs and the hydrophilicity or hydrophobicity of the membrane.

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Pore size distribution was determined from solute permeability data for urea, glucose and sucrose as a function of Stokes radius. Regenerated cellulose membranes have more limited pore size distribution than polymethylmethacrylate membrane. The solute permeability of glucose oligomers (monomer to octomer) was calculated from clearance data obtained by dialysis experiments.

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Determination of solute permeability is essential for improving hollow fiber membranes for clinical dialysis. To develop a new method of determining such permeability more simply and accurately, the authors employed light traveling along quartz optic fibers, which is well suited for spectroscopic and continuous measurements of solute concentration in narrow hollows. The resent paper describes the novel method of determination of the diffusional permeability of hollow fiber membranes from time-dependent absorbance data. We confirmed that the Lambert-Beer's law was applicable to dilute solutions. Values for solute permeability obtained by this novel method are almost agreement with those by radioisotope method and overall mass transfer coefficients fran clearance data. This study suggests the possibility of simulaneous determination of solute permeability for mixed solutes at various wavelengths giving maximal absorbance to each solute.

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Influence of bicarbonate concentration in dialysate on calcium (Ca) flux during hemodialysis was studied in 18 patients with hemodialysis. Each patient was dialysed four times using the four different dialysates with the different Ca concentration (3.5 or 2.5mEq/l) and with the different bicarbonate concentration (30 or 25mEq/l). In the post-dialysis, the increase of blood pH, plasma total Ca and ultrafiltrable Ca was large using the high concentration of bicarbonate at the same Ca concentration of dialysate. In the post-dialyzer site, the ultrafiltrable Ca increased using the high bicarbonate concentration of dialysate. These results suggest that Ca transport from dialysate to blood is influenced by the bicarbonate concentration of dialysate. Therefore, it is necessary to consider the bicarbonate concentration for the determination of the optimum concentration of dialysate Ca.

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Effective removal of inorganic phosphate by hemodialysis For the purpose of removing inoganic phosphate by hemodialysis, we examined the removal effect by using different dialyzers and by a change of acid-base balance. Dialyzers were used FB190M and FB190U. (FB190U. is high flux type.) Acid-base balance was changed by using bicarbonate recerculating dialysate. The first condition was bicarbonate concentration 27.5mEq/l, the second condition was 20mEq/l, for the first three hours and 27.5mEq/l for the last three hours.. The value of serum inorganic phosphate was investigated for six months on three chronic hemodialysis pathients.The average of Phosphate removal per six hours were 1233±230mg incase of FB190M, 1389±211mg in case of FB190U, 1508±94mg in case of FB190U and the second condition. In case of FB190u the average of serum inorganic phosphate before the concentration change was 6.6±1.2mg, and the average was 6. 2±0.7mg after six months changed the concentration change. Owing to the change of dialysis ways, phosphate removal volume was increasad, but serum inoganic phosphate was showed no change after a long period.

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A New device to monitor BUN and hematocrit simultaneously and continuously is reported. The BUN monitor consists of a urease-active chamber and ammonia gas electrode connected serially. The urease-active chamber is packed with about 70μl of cellulose gel, ‘Formil-cellulofine’, with 500μm of diameter and attached with urease. The hematocrit is also continuously monitored as an index of circulating blood volume. With this device, both BUN and hematocrit of a patient were monitored in the whole dialysis duration, the method should be of great helpful for analyzing so-called “disequilibrium syndrome”, and for developing safer acute dialysis.

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Monitoring and control systems for dialsis apparatus have been developed before. On the basis of our accumulated experience with such apparatus, we have newly developed a personal computer monitoring system for the dialysis unit, NCU-2.
A serial interface was used for communication, the PC-286V was used as the monitoring computer, and a 20MB hard disk and 4MB extension RAM were used as the auxiliary memory. By using the existing softwear, graphics are created for monitoring the dialysis unit so that equipment failure and system conditions may be easily understood.
By employ this system, information from the dialysis unit can be checked during dialysis, while a variety of information obtained during dialysis can be stored.

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We compared the dialysance by protein permeable meubrane (PPM) with that of ordinary membrane (NPM) by measuring drug clearance rate(Cl) In four chronic hemodialysis patients. After administering five kinds of drugs with different protein binding rates (PB); digoxin, famotidine, CZX, CFX and CMZ, the Cl of each drug was measured using BK-1.6, DUO-FLUX and EL201-12C as PPM and TFU-15M as NPM. Almost the same Cl were obteined for the lower PB drugs regardless of their molecular weights. For the higher PB drugs, to Cl were reduced, but the reductions were smaller in PPM. It is considered that the dialysance of the lower PB drugs by PPM is similar to that by NPM because they are removed mainly by diffusion, on the other hand, the dialysance of the higher PB drugs by PPM is superlor to that by NPM because of its protein permeability.

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We studied whether or not the hematocrit (Ht) values in 25 hemodialysis patients using high flux membrane dialyzers influenced on removal effeciency (removal rate, removal amount and clearance) of beta-2-microglobulin (B2-m). The removal rates were 30.1±11.9% at 24.0±3.1% of Ht values and 30.4±9.1% at 29.0±3.1%. In spite of the 11.5 points increases of Ht (from 25.2±3.8% to 36.7±5.6%), there were no changes in the removal rates (from 34.7±18.4% to 34.5±15.4%) . There was significant correlation between Ht and removal rates in only two cases among eleven cases. In two cases, one was positive, one, negative correlation coefficent. There was no constant trend in the relation of Ht and the removal rates. There was significant correlation between the serum B2-m concentration and the removal amounts, but no correlation between Ht and the removal amounts. The dialyzer clearances calculated from dialysate were 24.2±6.5ml/min on FB-150U. 18.7±2.5ml/min on FB-110U, 8.8±1.6ml/min on AM-UP-21 and 8.1±0.8ml/min on AM-UP-15. but the correlation between Ht and the dialyzer clearances was not significantly on all dialyzers. We concluded that Ht did not influenced the removal effeciency of B2-m using high flux membrane dialyzer.

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The present study elucidates diffusion characteristics for B2MG of newly-developed RCM. Dialysis experiments were made with 1251-labeled B2MG to obtain solute permeability. The solute permeability for B2MG of AM-EP-19 nearly equals that of FB-190UGA which are capable of removing B2MG by diffusion alone. This support satisfactory removal of B2MG by diffusion also using highly permeable dialysis membranes prepared from regenerated cellulose. Through analysis of data on the tritium-labeled water permeability and hydraulic permeability based on the tortuous pore model, we obtain 10nm, 48% and 1.7 as pore radius, surface porosity and tortuosity, respectively.

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Evaluation of β₂-microgiobulin removal by cuprammonium rayon membrane applied with enlargement of pore size. In vitro experiments were conducted by use of a cuprammonium rayon membrane (UP membrane) improved in the reduction rate of β₂-MG and EP membrane applied with enlargement of pore size, and permeation performances of substances primarily of β₂-MG were investigated.
Sieving coefficients of β₂-MG, albumin in bovine serum system were 0.45, 0.01 or less for UP membrane, and 0.65, 0.01 or less for EP membrane, respectively. Mass transfer coefficients of β₂-MG, urea were 0.21×10^-4, 12.6×10^-4cm/sec for UP membrane and 0.45×10^-4, 11.6×10^-4cm/sec for EP membrane, respectively.
From these results, it has been found that the EP membrane has sharp molecular weight cut-off characteristic, and little albumin is leaked out.
EP membrane can be expected to reduce larger amount of β₂-MG by the HD method than UP membrane.

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Nine types of modules with highly performed membrane were carried out in order to reveal their performances of BMG removal. During an in vitro study using human plasma, more than 2.0×10^-5cm/sec for overall mass transfer coefficient and more than 0.9 for sieving coefficient were obtained for ASAHI PAN 20CX2 and 17DX composed of polyacrylonitril(PAN) and Nipro FB-190U of cellulose triacetate(CTA). On the other hand, membrane adsorption and/or plugging for BMG was shown in every synthetic membranes, especially in polymethylmethacrylate (PMMA), not in cellulosic membranes.

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In an attemp t to clarify how effectively an intermittent or a continuous hemopurificat ion can reduced the plasma β₂-microg lobulin (β₂-MG) level we made kinetic models for the indivisual treatment, respectively, and estimated the changes in the plasma concentration following the treatment switch from a conventional HD too an HD or HDF with a β₂-MG permiable high performance membrane or continuous ones such as CAPD. The results indicated that in the case of an intermittent hemopurification steady decrease of the plasma concentration would not be obtained because of the rebound phenomenon between treatments. This tendancy is particularly conspicuous in patients whose initial plasma β₂-MG level is relatively lower among ESRD patients (eg.30mg/L) The results also indicated that in the case of a continuous one a steady decrease could be obtained however, CAPD would not offer this because of the extremely low peritoneal membrane clearance.

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To evaluate the leucocyte and platelet activity during hemodialysis treatment, we assessed the white blood cell and its differential count, platelet count, β-thromboglobulin (β-TG), platelet factor-4 (PF-4), thromboxane B₂ (TXB₂) and the nitroblue tetrazolium reduction ratio of neutrophil. In addition, lipids peroxidation products (MDA) were measured to estimate the influence of free radicals during HD. Transient and significant Leucocytopenia and thrombocytopenia were found. The number of neutrophil transiently decreased at the early phase of HD, but lymphocyte counts were stable during HD. PF-4, β-TG and TXB₂, released during platelet activation, were not found to have increased any, throughout the 4 hours after initiation of dialysis, compared with those made at the beginning. NBT reduction ratio of neutrophil was significantly reduced at 15 minutes after initiation of HD. Serum NDA levels were not significantly changed throughout HD. These results suggested that the activation of neutrophil and platelet during HD was not apparent, and free radical generation during one period of HD did not influence the producing of lipid peroxidation.

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This study was designed for elucidating the platelet/dialyzer interactions. This was achieved by measuring the intracellular calcium ion concentration of platelets using the calcium sensitive fluorescent probe (Fura-2). General observations are as follows; 1) In protein free condition the hydrophobic polyacryronitrile (PAN) membrane significantly actjvated the platelets, whereas the hydrophilic ethylene vinyl alcohol copolymer (EVAL) membrane did not activate the platelets. 2) The platelet activation induced by PAN membrane was passivated by preadsorbed proteins (fibrinogen, fibronectin and albumin) and supplementation of serum in platelets suspended buffer.

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The antithrombotic effect of newly developed surface modification of cellulose hemodialysis (HD) membrane (New MC) was evaluated by clinical studies. 5 stable hemodialysis patients were hemodialyzed by original cellulose (OC) and New MC, and minimum requirement dose of heparin (MD), and the change in celite activated coagulation time (CCT), plasma lipid, platelet releasing factor during HD with MD were determined. Although HD with OC required 2000±794U/HD of heparin, New MC required only 667±207U/HD. Prolongation of CCT was not observed in HDs with both dialyzer but CCT with New MC was shortened at the end of HD. Plasma lipid during HD with New MC did not change significantly. Elevation of platelet releasing factor was remarkably decreased during HD with New MC as compared with that with OC. These results indicate that the random movement of polyethylene glycol chain on cellulose membrane may prevent blood-membrane interaction and it suppressed the activation of platelet and coagulation factors. New MC is beneficial for HD patients with high bleeding risks.

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The modified Hemophan was developed in order to reduce the heparin adsorption to Hemophan, in which DEAE content was slightly reduced, compared with the original Hemophan. We compared dialyzers containing original Hemophan, modified Hemophan, Cuprophan and polymethylemethacrylate (PMMA) with regard to their biocompatibility and heparin adsorption during the course of hemodialysis treatment. As a result of test in vitro, modified Hemophan adsorbed less heparin than original Hemophan. Further, original and modified Hemophan adsorbed more amount of low molecular weight heparin than that of conventional heparin. As a result of test in vivo, modified Hemophan adsorbed less heparin than original Hemophan. So the amount of heparin required during hemodialysis decreased by 17.7%. The biocompatibility in view of the C₃ activation and the decrease in white blood cell count was as follows; PMMA>modified Hemophan=original Hemophan>Cuprophan. We observed no significant changes between modified Hemophan and original Hemophan in C₃ activation or white blood cell count. In conclusion, modified Hemophan is a useful membrane in the antithrombogenicity without loss of the biocompatibility.

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In order to clarify the effects of low molecular weight heparin as an anticoagulant for hemofiltration (HF) using high performance membrane (HPM) dialyzer, following study was conducted. In in vitro study, maximum clearance of LMWH reached to 50ml/min under 200ml/min of physiological saline perfusion. However, LMWH in human plasma has never been removed by HPM dialyzer. In clinical HF, the characteristics of LMWH were compared with those of unfractionated heparin (UFH). Neither UFH nor LMWH could be detected from filtrates. Plasma anti Xa activity rose significantly with both drugs during HF, but no prolongation of CCT was observed with LMWH and APTT was less prolonged with LMWH than that with UFH. The prolongation of Xa coagulation time (XCT) was proportional to the rise of plasma anti Xa activity, therefore a significant correlation was observed between XCT and plasma anti Xa activity. These results indicate that even when using HPM dialyzer, LMWH preserved its beneficial characteristics observed in usual HD.

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Bleeding complication caused by anticoagulant is a serious complication of CHF. The present study was undertaken to investigate relationship between various anticoagulantsand the incidence of bleeding complication during CHF and to decide optimal dose of the anticoagulant. The bleeding incidences with heparin, low molecular weight heparin and nafamostat mesilate were 7/11(64%), 3/15(20%) and 0/7(0%), respectively, indicating low molecular weight heparin and nafamostat mesilate should be chosen as anticoagulant for CHF. The optimal dose of those anticoagulant were less than 2.5unit/kg/hr and 0.1mg/kg/hr, respectively.

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Recently method on hemopurification is various then frequently increased on use. Continuously multiply on double lumen catheter (DLC) for temporary blood access of HD. We investigated through for effective DLC and reform on it since a few years. In this time we improved for DLC while trou ble of blood flow during extracorporeal circulation.For poor blood flow on HD, rotate DLC just a little and remove on distance of a few cm to the catheter. We modyfied a rotatable catheter by Cook company and attached with 4 ruber rings to siliding. Thereby blood flow recovered easily to this methods.

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The new ultrafiltration for the effective removal of microorganisms and pyrogens from the dialysis fluid was manufactured and clinically evaluated. The device was composed of polyethersulfone hollow fiber menbrane (molecular cut-off point=6, 000 dalton). Microorganisms were remoued prefectly. Endotoxins were elimiated significantly from 25.5±23.3 to 0.4±0.5pg/ml. The results revealed that the new divice could provide the sufficiently clean dialysis fluid with the least pyrogens, as well as without total micoorganisms.

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Bacteria and endotoxins in the dialysate were assayed in this study. As a result, Gram-negative bacteria such as Pseudomonas were found in the dialysate. The endotoxin concentration in the dialyysate was 50 to 70pg/ml, which suggested that the patient may be exposed to 7.5 to 10.5pg of endotoxins in one session of dialysis. In addition, using endotoxin extracted from Pseudomonas in the dialysate as the antigen, long-term hemodialysis patients were studied for entotoxin antibody. Although 4 out of 21 healthy volunteers tested positive to endotoxin antibody, 42 out of 98 hemodialysis patients tested positive and many of these patients were on the high flux membrane dialyzer. These results suggested that the dialysate should be kept endotoxin free.

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The cationically charged membrane was employed to separate urea and co-existing cations to avoid competitive adsorption by the ion-exchangers in the filtrate regeneration type artificial kidney. A high separation efficiency of urea from co-existing cations was obtained with the charged membrane but not by the commercially available non-charged dialysis membrane (PAN). The adsorption isotherm study of required amount of ion-exchanger in solution without co-existing cations. These results indicated that the newly developed filtrate regeneration system with the charged membrane is highly promising for a wearable and portable artificial kidney.

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We developed a peritoneal dialysis (APD) cycler that automatically exchanges bags of dialysis solution for CAPD patients during the night sleep. To increase the ability of dialysis. patients to perform social activities, we attempted nightly PD during sleep using this system instead of bag exchanges during daytime activities. The compact apparatus, measuring 132×90×40cm and weighing 700g, consists of an electronic timer and a motor, and can be mounted on a Y-shaped transfer set. The motor opens and closes the valve to achieve infusion and drainage of fluids. The dialysis solution was warmed with Mareru. selftemperature-control plane heaters consisting of fine carbon particles and polymers. No changes were observed in the laboratory findings after the use of the apparatus for 6 months, but fullness of the stomach was an occasional complaint. Nightly PD using the simple APD cycler is useful for rehabilitation of dialysis patients and is effective for as many as i exchanges per day in case of reduced peritoneal function.

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Hemofiltration and hemodialysis with various substitution fluid or dialysate (acetate or bicarbonate, sodium and buffer concentration), were performed for investigating solutes removal. The ratios of solutes reduction space for BUN reduction space were greater in hemofiltration than in hemodialysis. Alternatins of body fluid osmolarity or pH had no influences on solutes removal existing in total body water (BUN, Creatinine, Uric acid) nor on solutes removal existing in extracellular space (B2-MG, Inuline). Intracellular solutes (Pi, K) removal was changed by pH and kinds of buffers. For the adequate removal of various, solutes, ultrafiltration method should be applied and composition of substitution fluid or dialysate should be into consideration.

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During 3 years 15 patients had hemodialysis because of postoperative acute renal failure. Operative methods were open heart surgery 3, great vascular surgery 8, digestive surgery 2, hepatic surgery 2. Etiology of the acute renal failure were hemorrhagic shock, cardiac shock, dissection of renal arteries and etc. About the patients who were necessary respirator and IABP, hemodialysis was performed in ICU. Local heparinization and use of FOY were applied on the patients of DIC and within one week after operation. As a result, 60 of the patients could be saved.

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We, however, sometimes encounter the cases difficult to manage with peritoneal dialysis, especially those with circulatory failure. We performed continuous veno-venous hemodialysis (CVVHD) for the management of acute renal failure in six infants (age of 3 days to 11 months); five postoperative renal failure (four congenital heart diseases and one Bochdalek hernia) and one fetal hydrops. In all infants, mechanical ventilation and inotropic therapy were necessary. A femoral or a jugular vein was cannulated with a 6.5Fr double lumen catheter as blood access. Pediatric blood circuit with dead space of 36ml was used. We combined plasma exchange equipment (Kurare, KM-8500) and an infusion pump, to make minute-monitoring of fluid balance possible. CVVHD was performed with the blood flow rate of 5-10ml/min and the dialysate flow rate of 1-5ml/min. We observed no major hemodynamic and other complications throughout the therapy. In all cases, plasma creatinine, BUN and base excess were improved after starting CVVHD. One of 6 infants survived and was switched to PD after 5 days of CVVHD. CVVHD is an effective and safe therapy for acute renal failure in critically ill infants.

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In an experimental study to prevent bacterial contamination in peritoneal dialysis (PD) by using catheters with percutaneous access devices (PAD) made of hydroxyapatite (HAp), two dogs couldsuccessfully survive for a long time (19 and 6 months) without any peritoneal or so-called ‘tunnel’ infection. One dog, in which we caused end-stage renal failure by subtotal ligation of the left renal arteries with the right nephrectomy, could survive for more than 6 months, and this long-term survival of an experimental uremic dog may be a world record. Long-term experiment of end-stage renal failure dog should contribute to many kinds of study about peritonial dialysis treatment.

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It is important to choose aseptic mechanical support for treatment of MOF cases, because they are so-called “immuno-compromised hosts”. Usual mechanical renal support require a exocorporeal circulation which might cause an invasion of microbe into the patient. CAPD, a simple and closed system invented for home-dialysis, has been used for renal insufficiency of MOF cases, and the results are satisfactory. We call this new approach Continuous Intensive Peritoneal Dialysis; CIPD. In this study, we present the merits of CIPD in comparison with the usual methods. CIPD group showed excellently lower mortality rate (21.4%) despite the highest APACHE II score on admission. BUN, serum creatinine and catecholamine doses decreased significantly after CIPD introduction. We conclude that CIPD should be the first choice of mechanical renal support for MOF case whose host defence is compromised.

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To prevent skin-exit infection, an important CAPD complication, we developed a transcutaneous connector made of Alumina ceramic. An Alumina ceramic is characteristically bio-inert, rigid and non-porous. The shape of the new connector was of simple cylindrical configuration so as to inhibit macrostress beneath the skin. To make contact with this connector in the body, a sillicon tube was made into Swanneck catheter with a disk-shaped dacron cuff at No. 2 position. We are now using this new transcutaneous connector made of Alumina ceramic on a CAPD catheter in 7 patients. There has been virtually no down-growht phenomenon in the skin around the connector, and the connector and tissue have remained in very close contact.

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Clearances of small molecular substances such as urea are very sensitive to the membrane permeability, also to the flow dynamics of dialysate and blood. Especially, the dialysate flow pattern is widely changed by the fiber packing condition. The results with X-rays CT photographs present the channeling and/or dead spaces in the dialysate flow pass. Hand made dialyzers which have different fiber packing density show the effect of flow dynamics on the solute mass transfer coefficient. Poor packing density dialyzer has small mass transfer rate. Blended dialyzers with PS and EVAL-D5 have higher mass transfer rate because of its good flow distribution and adsorption.

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Dalysate with acetate Na (D-A·Na) was changed to that with bicarbonate Na (D-B·Na) in 25 hemodialysis (HD) patients. Subjective symptoms were improved in eight out of 25 cases. There was no particular change in 13 cases. Subjective symptoms were worsened in four cases. Progress of anemia was observed in two out of the four cases. Anemia in one of the two was improved after changing from D-B·Na to D-A·Na. Hypertension was observed before HD therapyand was improved by HD therapy with D-A·Na in 11 out of 25 petients. Hypertension was relapsed in 6 out of 11 cases after changing from D-A·Na to D-B·Na. Acetate Na is thought tobe an anti-hypertensive drug for some HD patients with hypertension, because it has pharmachological action to dilate peripheral blood vessels.

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The ion transport phenomenon in multi ion system across a charged membrane was studied by the theory basing upon the Donnan equilibrium and Nernst-Planck equation and examined in vitro. Then, this theory was applied to the analysis of ion transport on hemodialysis. Ion permeability coefficient rate (P. C. R.), the index of ion transpot coefficient across a charged membrane, showed good agreement between the results obtained from the therapy and those from in vitro studies. The theoretical analysiss of the ion transport across a charged hemodialysis membrane clarified that in positive charged membrane, the excretion of HPO₄^2-, HCO₃^- and the entrance of CH₃COO^- were increased using acetate dialysate, and the excretion of HPO₄^2- and the entrance of HCO₃^- were increased using bicarbonate dialysate. HPO₄^2- excretion was also stimulated by adding the positive charged substances to dialysate. These results indicate that it is possible to predict the ion transport across a charged membrane theoretically, and the charged membrane may be useful to correct the electrolite disturbance effectively on hemodialysis therapy.

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The mechanism of electrolyte transport through dialysis membranes should be clarified to improve inorganic phosphate removal from patients on long-term hemodialysis. Permeability to inorganic phosphate of regenerated cellulose(RC) and polymethyimethacrylate (PMMA) membranes was determined with aqueous radioisotope (³²P)-labeled disodium hydrogenphosphate at varying inorganic phosphate concentrations. We measured permeability to inorganic phosphate in bovine serum and compared with the permeability in aqueous disodium hydrogenphosphate. Zeta potential of RC and PMMA membranes was measured by the streaming potential method. Inorganic phosphate concentrations ranging from 3.33 to 66.6mEq/l don't affect the permeability to inorganic phosphate which increases significantly with inorganic phosphate concentration at concentraions from 66.6 to 100mEq/l and is insensitive to the inorganic phosphate concentration at a concentration of >100mEq/l. Permeability to inorganic phosphate in bovine serum is higher than that in aqueous solution.

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This paper presents the pre-diseased state model of the extracorporeal circulation focusing the endothelial cell (EC) injury at the transmembrane level. The EC injury was assessed as transmembrane stimulation by measuring the intracellular calcium ion concentration ([Ca]i). All activated humoral factors studies here ( kallikrein, bradykinin, factor Xa, thrombin, interleukin-1 and complement activated serum), induced elevation of [Ca]i of ECs. Especially, complement activated serum induced much higher level of [Ca]i than other factors. These suggested that complement activated serum induced the EC activation and membrane injury. Thus, the pre-diseased state model developed here may simulate EC injury of hemodialysis patients.

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We have investigated a new Push and Pull HDF using two blood pumps. This system consists of four parts: [1] arterial pump (A·P) [2] venous pump (VP) [3] controler for A·P and V·P, and [4] HFAK and OF controler. Spindle shaped tube made of silicone rubber was used in stead of bag to store fluid. If the flow of V·P is slower than that of A·P, positive pressure can be made in the circuit on the condition that the flow of AP is the stable. And if the flow of V·P is faster than that of A·P, negative pressure can be made. The strengs of the pressure and cycle could be changed freely by a programable controller.

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Techniques of membrane distillation have been developed in the field of the desalination of seawater and the dehydration of alcohol.We have tried for the removal of solute-free water from bovine blood by membrane distillation which have the advantages of high flux and outstanding selectivity at lower temperatures. In membrane distillation of which driving force is vapor pressure difference across hydrophobic membrane, the development of temperature and concentration polarization layers on either side of microporous hydrophobic membranes leads to the decline of permeation flux because of the reduction of vapor pressure difference across the membrane. Conventional theory of heat and mass transfer was applied to transport processes in membrane distillation to clarify effects of temperature and concentration polarization on water vapor permeability for ethylene glycol solution and bovine blood. In membrane distillation with bovine blood, the resistance of temperature polarization layer accounted for 61% of total permeation resistance at a stirring speed of 200r pm. At a stirring speed of 1000rpm the permeation resistance of membrane accounted for 52% of total permeation resistance. Destruction of temperature polarization layer and thinning of the membrane are essential for practical use.

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