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PubMed2004

Biosorption of Hg2+, Cd2+, and Zn2+ by Ca-alginate and immobilized wood-rotting fungus Funalia trogii.

Funalia trogii biomass was immobilized in Ca-alginate gel beads. The live and heat inactivated immobilized forms were used for the biosorption of Hg2+, Cd2+ and Zn2+ ions by using plain Ca-alginate gel beads as a control system. The effect of pH was investigated and the maximum adsorption of metal ions on the Ca-alginate and both live and inactivated immobilized fungal preparations were observed at pH 6.0. The temperature change between 15 and 45 degrees C did not affect the biosorption capacity. The biosorption of Hg2+, Cd2+ and Zn2+ ions on the Ca-alginate beads and on both immobilized forms was studied in aqueous solutions in the concentration range of 30-600 mg/L. The metal biosorption capacities of the heat inactivated immobilized F. trogii for Hg2+, Cd2+ and Zn2+ were 403.2, 191.6, and 54.0 mg/g, respectively, while Hg2+, Cd2+ and Zn2+ biosorption capacities of the immobilized live form were 333.0, 164.8 and 42.1 mg/g, respectively. The same affinity order on a molar basis was observed for single or multi-metal ions (Hg2+ > Cd2+ > Zn2+). The Langmuir and the Freundlich type models were found to exhibit good fit to the experimental data. The experimental data were analyzed using the first-order (Langergren equations) and the second order (Ritchie equations). The experimental biosorption capacity with time is found to be best fit the second-order equations. The alginate-fungus system could be regenerated by washing with a solution of hydrochloride acid (10 mM). The percent desorption achieved was as high as 97. The biosorbents were reused in five biosorption-desorption cycles without significant loss of their initial biosorption capacity.

Adsorption↗
PubMed2004

Kinetic and equilibrium studies in removing lead ions from aqueous solutions by natural sepiolite.

The capacity of sepiolite for the removal of lead ions from aqueous solution was investigated under different experimental conditions. The Langmuir and Freundlich equations, which are in common use for describing sorption equilibrium for wastewater-treatment applications, were applied to data. The constants and correlation coefficients of these isotherm models for the present system at different conditions such as pH, temperature and particle size were calculated and compared. The equilibrium process was well described by the Langmuir isotherm model and the maximum sorption capacity was found to be 93.4 mg/g for the optimal experimental condition. The thermodynamic parameters (DeltaG(o), DeltaH(o) and DeltaS(o)) for lead sorption on the sepiolite were also determined from the temperature dependence. The influences of specific parameters such as the agitation speed, particle size and initial concentration for the kinetic studies were also examined. The sorption kinetics were tested for first order reversible, pseudo-first order and pseudo-second order reaction and the rate constants of kinetic models were calculated. The best correlation coefficients were obtained using the pseudo-second order kinetic model, indicating that lead uptake process followed the pseudo-second order rate expression.

Environmental Pollutants↗
PubMed2005

Solid phase extraction and determination of sub-ppb levels of hazardous Hg2+ ions.

A simple, rapid and reliable method has been developed to selectively separate and concentrate ultra trace amounts of mercury(II) ions from aqueous samples for its highly sensitive measurement by cold vapor atomic absorption spectrometry (CV-AAS). The Hg(2+) ions were adsorbed selectively and quantitatively during the passage of aqueous samples through octadecyl silica membrane disks modified by isopropyl 2-[(isopropoxycarbothiolyl)disulfanyl]ethane thioate (IIDE). The retained Hg(2+) ions were then stripped from the disk with minimal amounts of 0.5 M hydrobromic acid (two 8 ml portions) as eluent, and determined by CV-AAS. The break-through volume of the method is greater than 3000 ml, which results in enrichment factors >150. Maximum capacity of the membrane disks modified with 10mg of the ligand was found to be 350+/-30 microg of mercury(II), and the limit of detection is 0.005 ng ml(-1). The effect of various cationic interferences on the recovery of mercury in binary mixtures was studied. The method was applied to the recovery of Hg(2+) ions from different synthetic and tap water samples, as well as the determination of mercury in human hair samples.

Environmental Monitoring↗
PubMed2005

Removal of metal ions from aqueous solutions by sorption onto rice bran.

A new sorbent (raw rice bran) was investigated for heavy metal ions removal from aqueous solutions. Rice bran characterisation was carried out in order to identify the functional groups possibly involved in the metal binding. The binding process was studied in terms of binding capacity and metal affinity. The adsorption equilibrium was well described by the Freundlich isotherm model. The negative Gibbs free energy values obtained in this study with rice bran confirm the feasibility of the process and the spontaneous nature of sorption.

Ions↗
PubMed2005

Comparison of linear and non-linear method in estimating the sorption isotherm parameters for safranin onto activated carbon.

Comparison analysis of linear least square method and non-linear method for estimating the isotherm parameters was made using the experimental equilibrium data of safranin onto activated carbon at two different solution temperatures 305 and 313 K. Equilibrium data were fitted to Freundlich, Langmuir and Redlich-Peterson isotherm equations. All the three isotherm equations showed a better fit to the experimental equilibrium data. The results showed that non-linear method could be a better way to obtain the isotherm parameters. Redlich-Peterson isotherm is a special case of Langmuir isotherm when the Redlich-Peterson isotherm constant g was unity.

Charcoal↗
PubMed2005

Influence of surfactant entrapment to dried alginate beads on sorption and removal of Cu2+ ions.

The removal of heavy metals has been investigated widely in recent years due to their potential health risk to human beings. In this study, the removals of copper from aqueous phase by alginate and SDBS entrapped alginate was investigated. First, a series of equilibrium sorption experiments were conducted at different initial pH values. Both equilibrium copper concentration and final pH values were observed. Then, a series of kinetic experiments were conducted and a second order rate relationship was fit to the experimental data. Equilibrium sorption experiments showed that the sorption of Cu+2 ions by 2% of SDBS entrapped alginate beads were greater than the plain and 0.5% of SDBS entrapped alginate beads. More H+ ion exchange occurred with the 2% of SDBS entrapped alginate beads, which was attributed to the increased number of the exchange sites on the alginate due to the sorption of surfactant to the beads. Kinetic sorption experiments showed that the equilibrium was reached faster for 2% of SDBS entrapped alginate beads. Results were successfully represented using second order kinetic model. Both equilibrium and kinetic experiments showed that the sorption of Cu+2 ions increased as the pH of the aqueous solution increased.

Adsorption↗
PubMed2005

Therapy of intractable pruritus with MARS.

INTRODUCTION: Pruritus is the most disabling symptom in patients with cholestatic liver diseases. Many drug therapies have been used for the treatment of these diseases, with different outcomes. The molecular adsorbent recirculating system (MARS) has been used in the treatment of intractable pruritus in cholestatic syndromes. We report our experience with MARS in 3 patients with intractable pruritus on the waiting list: 2 liver transplant recipients and a patient with primary biliary cirrhosis. PATIENTS AND RESULTS: Two middle-aged women and 1 middle-aged man, who were recipients of an orthotopic liver transplant for primary biliary cirrhosis, underwent three (n = 2) and two (n = 1) 6-hour sessions of MARS due to medically uncontrollable pruritus. All noted marked improvement of pruritus, with decreased bilirubin levels, but this improvement lasted only a few days in all cases. We observed no changes in transaminase or albumin levels, or prothrombin time. Complications included an episode of angina due to anemia caused by jugular catheter bleeding, and thrombocytopenia in all patients. CONCLUSIONS: MARS is an effective treatment for intractable pruritus in cholestatic liver diseases, although its beneficial effect is short. This extracorporeal liver device is safe, because most related adverse events are mild.

Adult↗
PubMedDate not supplied

The decrease in cytokine concentration during albumin dialysis correlates with the prognosis of patients with acute on chronic liver failure.

BACKGROUND AND AIM: The clearance of plasma cytokines by means of albumin dialysis (MARS) has been demonstrated in various studies involving patients affected by either acute liver failure (ALF) or acute on chronic liver failure. The aim of the study was to measure the plasma levels of TNF-alpha, IL-6, and IL-1beta in patients with ALF after each MARS treatment to evaluate the relationship between variations in cytokines levels and patient prognosis. MATERIALS AND METHODS: Ten patients with ALF undergoing several MARS treatments were enrolled (group 1). Blood samples were collected before and after each MARS treatment to measure TNF-alpha, IL-6, and IL-1beta, and other hematochemical parameters. We also enrolled 10 patients with ALF who underwent standard therapy (group 2) as well as a control group of 10 healthy subjects matched for sex and age (group 3). RESULTS: MARS reduced total bilirubin levels, biliary acids, BUN, ammonia, TNF-alpha, IL-6, and IL-1beta (P < .05). Moreover, the reduction in inflammatory cytokines levels and improved prognosis were related. CONCLUSIONS: We confirmed the therapeutic efficacy of MARS treatment for ALF, which appeared to be related to removal of toxins and inflammatory cytokines determine that which patients prognosis.

Adult↗
PubMedDate not supplied

Catholic university experience with molecular adsorbent recycling system in patients with severe liver failure.

BACKGROUND AND AIM: Molecular adsorbent recycling system (MARS) treatment is able to remove both hydrosoluble and small- and medium-sized lipophilic toxins. MARS plays an important role in modifying liver failure complications, such as hepatorenal syndrome and hepatic encephalopathy. We sought to evaluate the clinical efficacy and safety of a MARS device in a consecutive series of hepatic failure patients. MATERIALS: Twenty patients with acute liver failure, transplantation failure, or acute on chronic liver failure fulfilled the inclusion criteria of total bilirubin > or =10 mg/dL and at least one of the following: hepatic encephalopathy (HE) > or =II grade, hepatorenal syndrome (HRS) for chronic patients or total bilirubin > or =5 mg/dL and HE > or =I grade for acute patients. RESULTS: MARS was able to reduce cholestatic parameters and improve neurologic status and renal function parameters in all treated patients. We also observed an improvement in the 3-month survival rate compared to the expected outcome in patients with MELD scores between 20 and 29, as well as 30 and 39. CONCLUSIONS: Based on these results, we confirm the safety and clinical efficacy of MARS treatment, with the best results in patients with MELD score of 20 to 29. Further studies are necessary to confirm whether this treatment is able to modify patient outcomes and prognosis.

Bilirubin↗
PubMedDate not supplied

Molecular adsorbent recirculating system treatment for acute hepatic failure in patients with hepatitis B undergoing chemotherapy for non-Hodgkin's lymphoma.

Hepatitis B virus (HBV) is a serious cause of morbidity and mortality in hepatitis B surface (HBsAg) antigen-positive patients treated with chemotherapy. Because the hepatitis is related to HBV virological reactivation, application of effective antiviral therapy, such as Lamivudine, has been attempted. Despite the use of these antiviral agents at the time of clinical hepatitis, some HBsAg-positive patients still develop hepatic failure and die. We used the Molecular Adsorbent Recirculating System (MARS) (MARS Monitor; Teraklin AG, Rostock, Germany) to treat 5 HBsAg-positive lymphoma patients with acute hepatic failure due to chemotherapy despite lamivudine treatment. Before and after each treatment we monitored the parameters of neurological status (EEG, cerebral CT and Glasgow coma score), hemodynamic parameters, acid-base equilibrium and blood gases as well as hepatic and renal function. The inclusion criteria were these of the King's College Hospital. Statistical analysis by Student t method showed significant results (P < .01). Three of 5 patients are alive without signs of reactivation of viral or hematological diseases at 1 year follow-up. The 2 patients died because MARS treatment was started too late, with Glascow coma score grade IV, hemodynamic instability, and mechanical ventilator assistance. Despite the limited number of cases, we believe that MARS can be applied to patients with a high tolerance and yield good results, but the treatment has to start at the first signs of hepatic failure.

Adult↗
PubMedDate not supplied

One hundred sixteen cases of acute liver failure treated with MARS.

The various definitions of acute liver failure do not accurately reflect the differences in clinical signs and prognosis. Liver support devices to improve the clinical condition before liver transplantation (LT) were used in 13 patients with primary nonfunction, 24 with fulminant hepatitis, 17 were affected by delayed nonfunction, and 56 of acute on chronic hepatic failure. The average age of these patients was 41.8 years. The average number of applications of molecular absorbing recirculating system (MARS) was about 6 (range: 1-24). The mean length of application was about 9 hours (range: 8-20). MARS treatment was carried out in HLF patients with continuous acute-on-chronic hepatic failure dialisate flow similar to continuous veno venus hemofiltration (CVVH), albumin flow < 20% of hematic flow, heparin 5/10 UI/kg. In acute on chronic hepatic failure (AoCHF) patients, 6- to 11-hour (average 8.5) treatments were performed for a minimum of three treatments. The majority of patients were treated in the intensive care unit (ICU). Laboratory results were also monitored and showed progressive modification: bilirubin (before treatment 22.37 +/- 11.6 mg/dL, after treatment 11.36 +/- 7.5 mg/dL) and ammonium (before treatment 238.2 +/- 19 microg/dL, after treatment 115.4 +/- 12 microg/dL) showed significant change (P < .01). Lactates (before treatment 3.48 +/- 1.3 mmol/L, after treatment 1.76 +/- 1.1 mmol/L) and creatinine (before treatment 2.36 +/- 0.18 mg/dL, after treatment 1.26 +/- 0.67 mg/dL) also showed significant changes (P < .02 and P < .04). Glasgow Coma Score (GCS) went from 8.6 +/- 1.4 to 11.9 +/- 3.9 (P < .05). The mean middle cerebral artery flow (V media) went from 46 cm/s/26-59) to 73 cm/s (52-106) representing decreased cerebral edema, a difference that was not significant. INR scores (before treatment 2.4 after treatment 1.8) also showed no significant change. The MARS can be applied with tolerability for long periods for patients with PDF and FH as a bridge to transplant. In patients with PDF, it is used for a waiting recovery of the transplanted organ. Therefore MARS can also limit the necessity to perform further transplants.

Adult↗
PubMed2005

Experience of Mars therapy with and without transplantation in 101 patients with liver insufficiency.

Liver support devices are used to treat life-threatening organ dysfunction until a hepatic graft is available or recovery of the native liver. We used a blood purification system--molecular adsorbent recycling system (MARS)--that is based on removal of both protein-bound and water-soluble substances and toxins. Within 2.5 years we treated 101 patients, who were stratified to three subgroups: acute liver failure (ALF; n = 56), acute decompensation in chronic liver failure (AcOCh; n = 35) and liver graft failure (n = 10). MARS seems to be a promising therapy for ALF, allowing the patient's own liver to recover or to gain enough time to find a liver graft. The most promising results, namely the highest number of livers to recovery were observed among acute patients with liver failure due to a toxic etiology. However, we did not discover much benefit of MARS for patients with AcOCh without liver transplantation.

Alanine Transaminase↗
PubMedDate not supplied

The use Prometheus FPSA system in the treatment of acute liver failure: preliminary results.

UNLABELLED: The preliminary outcomes of patients with acute liver failure treated with the Prometheus Fractionated Plasma Separation and Absorption (FPSA) system are presented herein. PATIENTS AND METHODS: The procedures were performed in 13 patients (4, intoxication by Amanita phalloides; 4, unknown reason; 3, acetaminophen intoxication; 1, Wilson disease, and 1, liver insufficiency after hemihepatectomy owing to metastases of colon adenocarcinoma). The patients were qualified for the procedure according to the King's College Hospital criteria. The patients' general status was assessed on basic of GCS, UNOS, and the 4-grade encephalopathy classifications. The procedures were performed with the Prometheus 4008H Fresenius Medical Care unit. RESULTS: The 29 procedures were of mean duration 6.5 hours. There were statistically significant reductions in total bilirubin, ammonia, and aminotransferase levels. In addition, the procedures corrected water, mineral, and carbohydrate disorders. One patient did not require liver transplantation. Seven patients received liver transplants: three patients with positive outcomes; two died due to septicemia within 30 days perioperatively, one died at 6 months after OLT owing to respiratory failure; and one, owing to hemorrhagic diathesis. Four patients did not receive a liver transplant because of lack of a organ, no consent for the surgery, or neoplastic disease with metastases. CONCLUSIONS: The Prometheus FPSA-System was an effective detoxication method for patients with acute liver failure. The system was useful as a symptomatic treatment before liver transplantation allowing a longer wait for a graft.

Biomarkers↗
PubMed2006

Intractable pruritus in patients with hepatitis C virus.

Intractable pruritus is one of the most common symptoms of chronic liver disease, especially experienced by patients with prolonged cholestasis. It can become the most distressing symptom in patients affected by chronic liver disease, causing a reduction in quality of life, interfering with daily activities, and leading to sleep deprivation or contributing to psychological disturbances up to suicide ideation. Therefore, pruritus that does not respond to medical therapy is an indication for liver transplantation. We treated nine patients with hepatitis C virus affected by intractable pruritus with the molecular adsorbent recirculating system. In each patient, liver function, renal function, and hemodynamic variables were evaluated before and after the treatment. Before undergoing the treatment each patient underwent abdominal ultrasound or computed tomography scan to exclude organic causes for pruritus. We observed a decrease in total bilirubin, creatinine, and bile acids together with a significant improvement in Visual Analog Scale for staging of pruritus in all the patients. Due to the small number of patients the results were not significant.

Adult↗
PubMed2006

Treatment of refractory cholestatic pruritus with molecular adsorbent recirculating system (MARS).

UNLABELLED: Pruritus is a common complication of cholestatic liver diseases or liver graft dysfunction. Current medical therapies lack efficacy. The molecular adsorbent recirculating system (MARS) represents an interesting therapeutic option. Our objective was to report our experience in the management of four patients with intractable pruritus with MARS. PATIENTS AND METHODS: The MARS treatment cycle included three consecutive treatments, each of 8 hours duration. The four patients with intractable pruritus who were treated had primary biliary cirrhosis/autoimmune hepatitis overlap syndrome (n = 1), ductopenic allograft rejection (n = 2), or posttransplant cholestatic HCV recurrence (n = 1). Intensity of pruritus was documented 24 hours before as well as 24 hours, 7 and 30 days after MARS therapy, and at the end of follow-up. We measured complete blood cell counts, glucose, BUN, creatinine, sodium, potassium, AST, ALT, GGT, alkaline phosphatase, bilirubin, prothrombin activity, and activated partial thromboplastin time. RESULTS: MARS therapy was well tolerated. Patient 1 experienced temporal relief of pruritus, but needed another MARS cycle because of relapse. Patient 2 experienced partial and temporary relief of pruritus, was listed for retransplantation, and received a liver graft 2 months later. Patient 3 showed a dramatic reduction in the degree of pruritus with MARS. Pruritus in patient 4 decreased promptly with MARS therapy and conversion of immunosuppression to tacrolimus, thereby avoiding retransplantation. CONCLUSION: MARS therapy is a promising, safe therapeutic option to treat refractory pruritus caused by cholestatic liver disorders.

Adult↗
PubMed2004

A high-resolution titrator: a new approach to studying binding sites of microbial biosorbents.

The high-resolution potentiometric titration was used as a physico-chemical method to study the acid properties of selected biosorbent materials in order to quantify the functional acidic groups for sorption and to determine their affinities by considering their partial or total ionization equilibrium reactions. The Gran's method and the Henderson-Hasselbach's equation were employed in establishing the partition of the total acidity as associated with strong, weak and very weak acidic chemical active groups. The differences in the total organic acidity (A(TO)) for the two selected types of bacteria and two mycelia revealed by this method were explained by the chemical composition of their cell walls. The total organic acidities obtained were 3.87 me g(-1) for Thiobacillus ferrooxidans, 1.31 me g(-1) for Corynebacterium glutamicum, 0.81 me g(-1) for Aspergillus niger and 2.54 me g(-1) for Rhizopus arrhizus. The links between the activity of protons and the sorption capacities of the selected bioorganic matters were established. Sorption of lead by C. glutamicum and R. arrhizus biomass indicated an optimum pH of 6. It appeared that 64% (Pb(uptake)=0.48 me g(-1)) and 38% (Pb(uptake)=0.28 me g(-1)) of A(TO) were involved during lead sorption onto R. arrhizus and C. glutamicum, respectively. The applications of titration techniques become a powerful tool for the characterization of heterogeneous materials involved in biosorption and bioremediation processes.

Aspergillus niger↗
PubMedDate not supplied

Dispelling myths in the treatment of hepatic encephalopathy.

CONTEXT: Guidelines for the treatment of hepatic encephalopathy suggest ammonia reduction as the main focus, based on strategies to reduce ammonia's generation and absorption in the colon by using lactulose and a reduced protein diet. STARTING POINT: Two studies provide compelling and provocative data questioning the relevance of these interventions. Bodils Als-Nielsen and colleagues, in a systematic review of randomised trials, found insufficient evidence about whether non-absorbable disaccharides are beneficial (BMJ 2004; 328: 1046-50). In a small randomised study, Juan Cordoba and colleagues showed that diets with normal protein content can be administered safely during episodic hepatic encephalopathy due to cirrhosis and that protein restriction does not have any beneficial effect during such episodes (J Hepatol 2004; 41: 38-43). WHERE NEXT: Two approaches to new therapies for hepatic encephalopathy are needed. First, it is important to focus on the interorgan metabolism of ammonia. The small intestine and kidneys might be important producers of ammonia, and muscle is an important organ that can remove ammonia. Novel therapies targeting these organs reduce ammonia. Second, research is needed to explore factors other than ammonia that might be important in hepatic encephalopathy, including the synergistic role of inflammation. The lack of conclusive data about the efficacy of any treatment supports the view that placebo-controlled trials of newer agents are needed and ethical. The emphasis should shift to aggressive management of the precipitating event.

Ammonia↗