***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: One hundred out patients on chronic haemodialysis with polymethylmethacrylate ( PMMA ) membrane dialyzer  were r and omly chosen . A control group of 100 likewise r and omly chosen out patients were treated with cuprophane membrane dialyzer . In both groups the treatments lasted for one year . Comparison of the test results revealed that Si , Al and β2M.G levels could be reduced in patients on chronic HD with PMMA This biocompatibility of the new cellulosic membrane hemophane ( HE ) is compared to that of cuprophane ( CU ) in ten maintenance hemodialysis ( HD ) patients dialyzed on the two types of membranes in r and omized order , under otherwise similar technical conditions .  Total white blood cell ( WBC ) and differential counts , blood concentrations of C3a , and C3d and histamine are determined at start of dialysis ( TO ) and 10 , 20 and 180 minutes thereafter . HE is distinct from CU in exerting a minor effect on the generation of C3a , a minor drop of leucocytes during the course of dialysis ( P less than 0.01 ) and also by a lesser increase in blood histamine concentration ( P less than 0.05 ) . Histamine liberation is observed on CU together with the generation of anaphylotoxin C3 and with a diminution of circulating basopolymorpho-nuclear cells . According to the variations observed for these three parameters ( C3a , leucocytosis and blood histamine concentration ) , HE appears as being more biocompatible than CU There is increasing evidence that the biochemical and cellular phenomena induced by blood/ membrane/dialysate interactions contribute to dialysis-related intradialytic and long-term complications . However , there is a lack of large , prospect i ve , r and omized trials comparing biocompatible and bioincompatible membranes , and convective and diffusive treatment modalities . The primary aim of this prospect i ve , r and omized trial was to evaluate whether the use of polysulfone membrane with bicarbonate dialysate offers any advantage ( in terms of treatment tolerance , nutritional parameters and pre-treatment beta-microglobulin levels ) over a traditional membrane ( Cuprophan ) . A secondary aim was to assess whether the use of more sophisticated methods consisting of a biocompatible synthetic membrane with different hydraulic permeability at different ultrafiltration rate ( high-flux hemodialysis and hemodiafiltration ) offers any further advantages . Seventy-one Centers were involved and stratified according to the availability of only the first two or all four of the following techniques : Cuprophan hemodialysis ( Cu-HD ) , low-flux polysulfone hemodialysis ( LfPS-HD ) , high-flux polysulfone high-flux hemodialysis ( HfPS-HD ) , and high-flux polysulfone hemodiafiltration ( HfPS-HDF ) .  The 380 eligible patients were r and omized to one of the two or four treatments ( 132 to Cu-HD , 147 to LfPS-HD , 51 to HfPS-HD and 50 to HfPS-HDF ) . The follow-up was 24 months . No statistical difference was observed in the algebraic sum of the end points between bicarbonate dialysis with Cuprophan or with low-flux polysulfone , or among the four dialysis methods under evaluation . There was a significant decrease in pre-dialysis plasma beta 2-microglobulin levels in high-flux dialysis of 9.04 + /- 10.46 mg/liter ( 23 % ) and in hemodiafiltration of 6.35 + /- 12.28 mg/liter ( 16 % ) , both using high-flux polysulfone membrane in comparison with Cuprophan and low-flux polysulfone membranes ( P = 0.032 ) . The significant decrease in pre-dialysis plasma beta 2-microglobulin levels could have a clinical impact when one considers that beta 2-microglobulin accumulation and amyloidosis are important long-term dialysis-related complications BACKGROUND Hyperhomocysteinaemia is a putative risk factor for atherothrombotic cardiovascular disease in the haemodialysis population .  High-dose vitamin B therapy does not entirely normalize elevated plasma total homocysteine ( tHcy ) levels in haemodialysis patients . Alternative therapies to reduce tHcy further are therefore required . Modifications of the dialysis regimen may result in a better removal of Hcy . We examined the effect of dialyser membrane pore size on tHcy levels in vitamin-replete chronic haemodialysis patients . METHODS Forty-five haemodialysis patients were dialysed during 4 weeks with a low-flux , a high-flux and a super-flux membrane , in r and om order . Pre-dialysis  tHcy  was determined at baseline and every 4 weeks . In 18 patients , plasma tHcy before and after dialysis and dialysate tHcy concentrations were measured . RESULTS Pre-dialysis tHcy decreased significantly during 4 weeks super-flux dialysis ( -14.6 + /- 2.8 % ) , whereas it remained stable during high-flux ( + 0.5 + /- 2.4 % ) and low-flux dialysis ( + 1.7 + /- 3.2 % ) . The homocysteine reduction ratio was not different for the three membranes : 0.39 + /- 0.03 for the super-flux , 0.47 + /- 0.02 for the high-flux and 0.39 + /- 0.02 for the low-flux dialyser . The amount of Hcy recovered in the dialysate during a single dialysis session was also similar : 117.5 + /- 3.6 micro mol during super-flux , 95.3 + /- 11.5 micro mol during high-flux and 116.5 + /- 11.6 micro mol during low-flux dialysis . CONCLUSION Super-flux dialysis significantly lowers tHcy in chronic haemodialysis patients . Improved removal of middle-molecule uraemic toxins with inhibitory effects on Hcy-metabolizing enzymes , rather than better dialytic clearance of Hcy itself , may explain the beneficial effect of the super-flux membrane Pruritus is one of the major unsolved problems for patients receiving regular hemodialysis . In this study , we conducted a 6 month prospect i ve and crossover trial to investigate the effect of polymethylmethacrylate ( PMMA ) membrane for renal itching . We also examined the role of the tumor necrosis factor (TNF)-alpha system for pruritus in hemodialysis patients . We assessed the degree of skin itching and measured circulating levels of TNF-alpha and soluble TNF receptors ( sTNFR-I , sTNFR-II ) in 19 patients using hemodialysis , complicated by prolonged severe pruritus for 6 months .  Serum sTNFR-I and II levels were significantly elevated in hemodialysis patients compared to normal subjects . Serum sTNFR-II levels were significantly and negatively correlated with serum albumin ( r = -0.602 , p = 0.007 ) . A significant positive relationship was also found between sTNFR-I and erythropoietin dosage ( r = 0.554 , p = 0.016 ) . However , no association was found between the degree of pruritus and circulating sTNFR-I and II values . Skin itching scale was significantly decreased from 2.7 + /- 0.2 to 2.1 + /- 0.3 following the use of PMMA membrane for 3 months ( p < 0.05 ) . In contrast , there was no change in itching scales during 3 months of conventional therapy ( 2.2 + /- 0.3 versus 2.2 + /- 0.3 , p = NS ) . PMMA itself did not affect serum TNF-alpha and sTNFR values as well as conventional dialyzer membranes . These findings suggested that the PMMA dialyzer can improve renal itching not mediated through the modification of the TNF-alpha system A crossover study to compare the effects of  seven different dialysers on blood gas conditions during dialysis using acetate-containing dialysate was carried out at five centres in four countries . A significant decrease in pO2 was noted at both 15 and 60 min after the start of dialysis for all dialysers , with the greatest decrease at 60 min . Filtral caused the greatest reduction and F 60 the least change at both 15 and 60 min . These differences were statistically significant according to the ANOVA multiple-range test for variance . pCO2 also declined by 1.0 - 2.7 mmHg at 15 min and by 0.7 - 3.8 mmHg at 60 min . The delta pCO2 was comparable across dialysers and no significant differences were found . Although pH showed no change at 15 min , it was slightly but significantly increased at 60 min across all dialysers compared to predialysis values . There were no statistical differences between dialysers . Calculated blood bicarbonate content significantly decreased at 15 min and recovered at 60 min . Along with the greater decrease in pO2 , a larger loss of total CO2 was noted for Filtral . On the other h and F 60 caused the least change in total CO2 . This difference may be due to membrane characteristics affecting the diffusion coefficient for O2 , CO2 , and bicarbonate . Multifactorial mechanisms are likely to be involved , but reflex hypoventilation and an increase in O2 consumption also contributed to hypoxaemia in this study BACKGROUND Half of the dialysis population suffers from hyperphosphataemia , which is now recognized as a major factor of haemodialysis ( HD ) morbidity and mortality . Current control is focussed on reducing dietary phosphate intake and diminishing absorption using phosphate binders , whereas control and quantification of phosphate removal by HD is undervalued . The aim of this prospect i ve study was to develop a simple , bedside formula to estimate dialytic phosphate removal in stable HD patients . METHODS This was a prospect i ve , r and omized trial . Phosphate and urea elimination were assessed in a representative group of patients at two dialysis centres using r and omly different dialysers ( 1.3 - 2.4 m(2 ) ) . Quantification was performed by partial dialysate collection , concentration measurements in blood and effluent dialysate spot sample s , and Kt/V(urea ) during st and ard high-flux HD . Multiple linear regression analyses were used in 77 % of all data sets to generate an equation to predict phosphate removal . The formula was vali date d in the remaining 23 % of data sets , in the same group of patients using a large capillary filter , and in diabetic patients treated with a small dialyser at different blood flows ( 200 , 250 , and 300 ml/min ) . RESULTS A formula allowing quantification of phosphate removal within one HD session was developed in 18 of 74 patients during 41 treatments ( 137 out of 177 data sets ) and was determined as : M(PO4pred)=0.1 t -17 + 50c(ds60)+11c(b60 ) , where t is treatment time in min , c(ds60 ) and c(b60 ) are phosphate concentrations in dialysate and plasma measured 60 min into HD in mmol/l , and M(PO4pred ) is estimated phosphate removed in mmol . The precision was remarkable ( r(2)=0.92 - 0.94 ) . The comparison of phosphate and Kt/V(urea ) showed a significant association ( r(2)=0.28 ) , albeit with remarkable scatter . CONCLUSIONS We present the first approach to quantify phosphate removal during high-flux HD by a bedside formula . Only 28 % of the variation in phosphate removal was explained by Kt/V(urea ) . It appears that other factors not adequately accounted for by Kt/V(urea ) affect phosphate removal . Therefore , we propose an individual control and quantification of phosphate removal in HD In vitro experiments have related anaphylactoid reactions in patients treated with angiotensin-converting enzyme ( ACE ) inhibitors during dialysis with AN69 membranes  to excessive bradykinin generation using this negatively charged dialysis membrane . In the present clinical trial plasma bradykinin levels were followed during the early phase of dialysis in 10 patients , not being treated with ACE inhibitors  , using AN69 , cuprophane , and polysulfone membranes . Bradykinin was measured after extraction by radioimmunoassay . During this study one episode of anaphylaxis occurred during dialysis with the AN69 membrane .  Blood sample s were collected during the first 5 min of the adverse reaction and showed a more than 100-fold increase in the venous effluent of the AN69 dialyzer ( baseline 40 + /- 3 vs. 4,900 + /- 130 fmol/ml after 5 min ) . Even though none of the patients received ACE inhibitors , there were 4 more asymptomatic individuals who displayed a more than two-fold increase in their plasma bradykinin concentrations in the venous effluent of the AN69 dialyzer . When these patients were treated either with cuprophane or with polysulfone dialyzers , no significant bradykinin formation was detected , nor were there any adverse events . Taken together , these findings show that anaphylactoid reactions 
    Output:
    
When analysed for change in ss(2 ) microglobulin , a fall was only noted with high-flux membranes .
We found no evidence of benefit when synthetic membranes were compared with cellulose/modified cellulose membranes in terms of reduced mortality no reduction in dialysis-related adverse symptoms .
Despite the relatively large number of RCTs undertaken in this area none of the included studies reported any measures of quality of life