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Results for “Sorption Detoxification”

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At least 91 records · Page 5Linked to original sources

PubMed2002

Patient safety technology for microadsorbent systems in extracorporeal blood purification.

Alternative technologies for extracorporeal blood purification systems based on microadsorbents in suspension are discussed. Principally, microadsorbents offer higher efficiency and flexibility when compared to conventional column-based adsorption systems. Systems already clinically employed (e.g., BioLogic DT) or close to clinical application (e.g., the microspheres-based detoxification system, MDS) are described. The MDS technology, in particular, is characterized by efficiency and a high degree of flexibility with respect to both the use of different adsorbents as well as the combination with hemodialysis/hemofiltration therapy. It was designed for continuous use in intensive-care units, but enables also the removal of low-density lipoprotein, fibrinogen, autoimmune antibodies, immune complexes, and other pathophysiologically relevant substances. Alternative anticoagulation regimes and safety systems on fluorescence sensor technology have recently been developed for the MDS and are presented in this paper.

Adsorption↗

PubMed2006

Poly(ether imide) scaffolds as multifunctional materials for potential applications in regenerative medicine.

This article gives an overview of scaffolds that can be prepared from poly(ether imide) (PEI). These scaffolds were developed for extracorporeal blood detoxification processes in which specific compounds from blood or plasma are removed selectively. Both the preparation of porous microparticles and the preparation of hollow fibers are described. Commercially available particulate support materials have the disadvantage of a low accessibility of the internal pore system, a poor flow-through behavior and low adsorption specificity. Thus, novel support materials with optimally adapted properties profiles are needed. The second part of this article shows some recently developed highly asymmetric PEI hollow fibers. PEI scaffolds can be considered multifunctional because they combine separation characteristics, biocompatibility, sufficient biostability, and the possibility of creating tailor-made biofunctional surfaces.

Biocompatible Materials↗

PubMedDate not supplied

Detoxification of aflatoxin-polluted peanut cakes with monomethylamine/Ca(OH)2: pilot industrial application, nutrition experiments, toxicity evaluation.

The process described has been studied up to an industrial pilot scale. In this article this article we summarize the basic knowledge on the process and the technological conditions of pilot application for detoxifying peanut cakes polluted by up to 3,500 ppb Aflatoxine (2,300 ppb B1). The nutritional experiments carried out on rats and other mammals are described, and the toxicological and biochemical evaluation of the cakes on Bacillacea are reported and discussed. The data collected show that the MMA/Ca(OH)2 process offers promising possibilities for industrial application on the basis of technological and economic criteria, as well as from the point of view of efficiency and safety.

Aflatoxins↗

PubMed1995

Scanning electron microscopic investigations of surface treated large-bore catheters used for extracorporeal detoxification methods.

Typical complications caused by surface properties of synthetic catheter implants are infection, thrombosis, and stenosis. New methods for surface modification with the aim of reducing such complications are ion beam-based technologies. In our study 109 large-bore catheters without (n = 42) and with treated surfaces with silver (n = 39) or silicone (n = 28) were inserted into the interna jugular and the subclavian veins and were used for extracorporeal detoxification methods. After removal, the catheters were investigated with scanning electron microscopy (SEM) and for bacterial colonization. In 42 large-bore catheters without surface treatment deposits of fibrin, protein and blood cells were seen on the inner and outer surface. Bacterial colonization was observed in 38.1%. In contrast, the catheters with treated outer surfaces showed a very low thrombogenicity and a low contamination rate of 8.9%. The ion beam-based technologies reduce the thrombogenicity and infection rates of the catheter surfaces. In comparison to catheters without treated surfaces, catheters with surface treatment are good alternatives in blood contacting applications ranging from hemodialysis to oncology.

Adsorption↗

PubMed2002

Effects of sorbent suspension dialysis on plasma amino acid levels in cirrhotic patients with refractory hepatic encephalopathy.

In cirrhotic patients, plasma amino acid levels are severely deranged. A decreased ratio of branched-chain to aromatic amino acids (Fischer ratio) has been implicated in the pathogenesis of hepatic encephalopathy. In this prospective study, we investigated the effects of extracorporeal detoxification on amino acid levels using a sorbent suspension dialysis system. Twenty patients with documented cirrhosis and hepatic encephalopathy grade II-III not responding to standard treatment were randomized to receive either six hours of sorbent dialysis and standardized conventional medical treatment or ongoing medical treatment alone. In contrast to previous uncontrolled studies, no significant effect on amino acid levels, Fischer ratio or clinical grade of hepatic encephalopathy was detected in either treatment group. In conclusion, a 6-hour treatment with sorbent dialysis did not significantly influence plasma levels of amino acids and did not ameliorate the clinical grade of hepatic encephalopathy.

Adult↗

PubMed1993

[Treatment of generalized purulent appendicular peritonitis in children].

Experience in the treatment of 137 children with a most severe and complicated course of generalized purulent peritonitis of appendicular genesis is generalized. It is shown that such patients must be concentrated in centers of pediatric surgery providing the possibility of applying a complex of diagnostic examinations and therapeutic measures, including purposeful antibiotic therapy, differentiated immunocorrection, and effective detoxification. The detoxification and immunocorrection effect of discrete plasmapheresis with two-stage "washing out" of the red cells is illustrated in the discussion of 22 cases. It is pointed out that in operations for generalized purulent peritonitis the abdominal cavity must not only be cleansed but also drained adequately and intubation of the intestine must be carried out with aspiration of its content for 3-5 days and application of enterosorption through an intestinal tube. A complex of organizational and therapeutic measures made it possible to reduce considerably the mortality rate in acute appendicitis and its complications in the Moscow Region.

Acute Disease↗

PubMedDate not supplied

[The use of donor blood plasma with a high titer of natural antiendotoxin antibodies, irradiated by ultraviolet light, in the combined detoxification therapy of peritonitis].

The ultraviolet (UV) irradiation of donor blood plasma with an elevated level of natural antibodies to Re-glycolipid with doses ranging from 100 to 200 J/m2 has been found to lead to a statistically significant rise in its protective activity. The use of such plasma in clinical practice has made it possible to decrease the frequency of lethal outcomes from 24.3% to 16.5% (p < 0.01), the occurrence of secondary infectious complications from 62% to 44.4% (p < 0.01) and the duration of patients' stay in a hospital by 6-8 days. These data make it possible to regard the use of UV-irradiated plasma with an elevated level of Re-antibodies as an effective method of the immunotherapy of septic complications caused by gram-negative bacteria.

Acute Disease↗

PubMed1991

[Detoxification in the combined intensive therapy of patients with multiple organ failure].

Studies of the influence of the UV irradiation of autologous blood (UVIAB) and hemosorption (HS) upon changes of indices of endogenous intoxication in patients with the syndrome of polyorganic insufficiency (SPOI) have shown that the isolated (without HS) UVIAB reduces toxemia and prevents the development of SPOI in patients without pronounced alterations of microcirculation. Using the UV irradiation of autoblood in patients with clinically marked alterations of the peripheral blood circulation increases toxemia at the expense of release of toxic products from the "disclosed" system of microcirculation. HS with the simultaneous taking the blood from the subclavian vein and abdominal aorta with using "Actilen" and return of the mixed blood into the peripheral artery interrupts and relieves the course of SPOI.

Adolescent↗

PubMed1999

Modeling and experimental comparison of the differential adsorption of B1 and G1 aflatoxins on mineral aluminosilicate surfaces.

Aflatoxins produced by Aspergillus fungus are secondary metabolites undergoing biotransformation rates in hepatic tissues and lipid peroxidation. Although the use of adsorbent materials became a common practice for feed grain detoxification, fundamental studies are needed to clarify the interaction occurring between mineral surfaces and organic molecules. We evaluated the differential adsorption of B1 and G1 on 10 adsorbent materials and compared it in vitro by means of fluorescence emission from solution. Three aluminosilicates showed no adsorption of B1 at all, whereas only one was inactive for G1 adsorption and seven of them showed 15.2 to 77.9% adsorption for B1 and 8.3 to 78% for G1. All these adsorbents were more selective toward G1 rather than B1 aflatoxins. This behavior can be explained by the presence of an additional cyclic ester in G1, which provides a higher electronic density to G1 molecules, thus forming more stable hydrogen bridges with respect to the cyclopentanone ring present in B1.

Adsorption↗

PubMed1996

Functional stability of porcine hepatocyte spheroids in various culture systems under 100% porcine and human plasma conditions.

To select an immobilization method suitable for bioartificial liver (BAL) modules utilizing porcine hepatocyte spheroids, functional activities were compared in various systems in 100% porcine and human plasma together with a synthesized medium. The spheroids, continuously suspended in rotating dishes or entrapped in collagen (CN) gel, expressed approximately two times higher ammonium detoxification abilities over conventional monolayers during 8 days of direct contact with 100% human or porcine plasma with a standardized inoculum cell number. No significant deterioration was observed in the abilities as compared with that in a synthesized medium. Although the cell number gradually decreased in rotational culture, the abilities per cells remaining on Day 10 were two times higher than in the CN-gel entrapped spheroids in all the media examined, presumably due to the diffusion limitation by the gel. Thus, in utilizing porcine hepatocyte spheroids in BAL modules, immobilization allowing direct contact of spheroids with perfused patient plasma was concluded to be possible and suitable.

Animals↗

PubMed2002

Extracorporeal support of the failing liver.

Successes in machine-based extracorporeal support for different organ functions stimulated research in the field of liver support approximately 50 years ago. Initial failure to improve outcome using detoxification methods like dialysis, blood and plasma exchange, or plasmapheresis over sorbents fueled interest in biologic liver support concepts using bioreactors or combined methods. New device configurations, technical improvement of existing detoxification methods, and the refinement in cell culture techniques led to a boost in research on biologic and nonbiologic approaches. Currently, many systems are in the preclinical phase or have entered clinical studies. A number of completed clinical trials have reported a favorable therapeutic impact of the most advanced solutions on the course and outcome of liver failure. Often, findings must be reconfirmed. However, current knowledge suggests that extracorporeal liver support can successfully stabilize liver function, improve the clinical condition of patients, and considerably improve survival in certain subgroups of patients with fulminant hepatic failure and acute decompensation of chronic hepatic failure. Although the initial focus of liver support methods was bridging to liver transplantation, bridging to recovery of organ function and treatment of intractable pruritus are now valuable indications.

Bioreactors↗

PubMed1994

[Indirect electrochemical detoxication in the combined treatment of purulent diseases in surgical practice].

The method of indirect electrochemical detoxification by means of sodium hypochlorite (NaClO) obtained by isotonic NaCl solution electrolysis on a [symbol: see text] device consists in modeling hepatic monooxygenase detoxifying function on cytochrome B-450. Indirect electrochemical detoxification was conducted in more than 200 patients with generalized abdominal pyo-inflammatory processes and marked intoxication syndrome. Sodium hypochlorite was used for intravenous treatment of endotoxicosis in concentrations of 600 mg/l and 300 mg/l in volumes of 1/10 and 1/6 CBV in patients with generalized fibrinopurulent peritonitis and pancreonecrosis and for local administration during programmed prophylactic treatment of the abdominal cavity. The detoxifying effect was best in patients with grade 2-3-intoxication (according to V. K. Gostishchev et al., 1989). Local use of NaClO was marked by a high necrolytic effect, antiseptic properties, capability for reducing the resistance of the microflora to antibiotics, etc. The work discusses the methods of hypochlorite application, indications, contraindications, possible complications and their prevention.

Adult↗

PubMed2002

Application of Molecular Adsorbent Recirculating System in patients with severe liver failure after hepatic resection or transplantation: initial single-centre experiences.

Acute liver failure after hepatic surgery is still plaqued with high mortality rate. Recently, a liver dialysis system (MARS) that allows detoxification of albumin-bound substances and may hereby support liver regeneration and patient's recovery has been developed. In the present study, we report our experiences with MARS dialysis in patients with liver failure after hepatic resection or transplantation. Between September 1999 and January 2001, five patients were treated with MARS (2-5 courses). Though beneficial effects such as improvement of encephalopathy and renal function as well as reduced bilirubin levels were recorded during MARS therapy, only one patient survived. Neither significant technical problems nor adverse effects occurred by using MARS dialysis. We conclude that in surgical patients, acute liver failure is usually part of a complicated clinical course affecting multipleorgan systems. Thus, it is difficult to determine the specific influence of MARS on patient's outcome. However, beneficial effects observed in our patients justify its continuous use and may stimulate further evaluation in controlled studies with surgical patients.

Hepatectomy↗

PubMed1994

Development of a bioartificial liver using isolated hepatocytes.

Severe liver disease is very often life-threatening and dramatically diminishes quality of life. Liver support systems based on detoxification alone have been proved ineffective because they cannot correct biochemical disorders. An effective artificial liver support system should be capable of carrying out the liver's essential processes, such as synthetic and metabolic functions, detoxification, and excretion. It should be capable of sustaining patients with fulminant hepatic failure, preparing patients for liver transplantation when a donor liver is not readily available (i.e., bridge to transplantation), and improving the survival and quality of life for patients for whom transplantation is not a therapeutic option. Recent advances in cell biology, tissue culture techniques, and biotechnology have led the way for the potential use of isolated hepatocytes in treating an array of liver disorders. Isolated hepatocytes may be transplanted to replace liver-specific deficiencies or as an important element of an auxiliary hybrid, bioartificial extracorporeal liver support device, which are important therapeutic applications for treating severe liver disease. Recently, several hepatocyte-based liver support systems have been proposed. Although there is no current consensus on its eventual design configuration, the hollow fiber hepatocyte bioreactor shows the greatest promise. Furthermore, application of tissue engineering technology, based on cell-surface interaction studies proposed by our group and others, has enhanced interest in the development of highly efficient hybrid, bioartificial, liver support devices.

Animals↗

PubMed2006

Fluidized bed adsorbent systems for extracorporeal liver support.

Acute liver failure based on acute-on-chronic liver failure (AoCLF) or on acute severe damage of the liver caused by different etiologies includes complex mechanisms resulting in severe disturbances of principle liver functions. In order to compensate the liver's function of detoxification as efficiently as possible, fluidized bed absorbent systems have been designed. In these systems, small particles with specific adsorption properties for toxins related to acute liver failure are applied. A special technology based on adsorbents in suspension has been developed under the guidance of our group and is prepared for clinical application during the coming year. This technology is called microspheres-based detoxification system (MDS) and is based on microadsorbents with a diameter of 1-10 microm which are recirculated in suspension. The safety of the MDS is guaranteed by the use of fluorescently labeled magnetic microparticles, which in case of a membrane-leakage are detected in the blood circuit by an optical system equipped with a magnetic trap. In vitro tests with two kinds of microadsorbents (a combination of a hydrophobic neutral resin and an anion exchange resin) showed excellent efficiency of the system with respect to adsorption capacity as well as to the kinetics of elimination of albumin-bound substances (e.g. unconjugated bilirubin or cholic acid) and of non-protein-bound substances (e.g. phenol). Moreover, using a plasma filter or the Albuflow filter as membrane filters in the blood circuit, the MDS technology offers the possibility to remove inflammatory mediators such as tumor necrosis factor-alpha (TNF) by additional use of specific adsorbents.

Adsorption↗

PubMedDate not supplied

Surface treated large bore catheters with silver based coatings versus untreated catheters for extracorporeal detoxification methods.

Infection, thrombosis, and stenosis are among the most frequent complications associated with blood contacting catheters. Because these problems are usually related to surface properties of the base catheter material, surface treatment processes, such as ion implantation and ion beam assisted deposition (silver based coatings), can be used to mitigate such complications. Because these ion beam based processes affect only the near-surface region (approximately the outer 1 microm), there is little effect on bulk material properties. This study evaluated silver coated large bore catheters used for extracorporeal detoxification. In a 122 patient prospective study, 156 large bore catheters were inserted into the internal jugular or subclavian veins. Seventy-eight surface treated catheters (SPI-ARGENT, Spire Corporation, Bedford, MA; n = 32 acute catheters, n = 45 long-term catheters) were Bambauer inserted in 55 patients. Seventy-eight untreated catheters placed in 67 patients served as controls (n = 35 acute catheters, n = 43 long-term catheters). After removal, the catheters were cultured for bacterial colonization using standard microbiologic assays. They were also examined using a scanning electron microscope (SEM). Bacterial colonization was observed in 15.4% of the treated catheters compared with 44.9% of untreated catheters. The SEM investigations showed all treated catheters to possess low thrombogenicity. Results of the study indicate that ion beam based processes can be used to improve thrombus and infection resistance of blood contacting catheters.

Adult↗

PubMed2002

Molecular adsorbent recirculating system: albumin dialysis-based extracorporeal liver assist device.

Extracorporeal liver assist devices have been used for more than five decades to support patients with liver failure. Numerous modifications have been made to both biological as well as mechanical liver assist devices. Possibly, an ideal liver assist device would be one that would perform optimal detoxification and synthetic functions of the liver, be simple to set up and yet be cost-effective. An albumin dialysis-based device that uses a hybrid albumin-impregnated membrane to get rid of albumin-bound toxins that circulate in abundance in liver failure, called the molecular adsorbent recirculating system (MARS) has been in clinical use for nearly four years now. Results with the use of this device in both acute and acute-on-chronic liver failure have shown consistent improvement in biochemical profile, resolution of encephalopathy, correction in hemodynamics, reduction in intracranial pressure and some improvement in the synthetic function of the liver. In a number of studies, albeit of small sample size, survival advantage has also been observed. The timing of initiation of therapy with MARS, duration of treatment, frequency of sessions and 'maintenance therapy' are still some of the unresolved issues with the use of this device. Large multicentric trials on the use of this technique are expected to throw light on these issues and help optimize the potential of this liver assist device.

Dialysis↗

PubMed1999

Microspheres based detoxification system: in vitro study and mathematical estimation of filter performance.

Because of the closed plasma (secondary) circuit in the Microspheres based Detoxification System (MDS), a convective blood purification system, the same amount of filtrated plasma is backfiltrated into the blood circuit. Therefore, there is no direct way to determine the ultrafiltrate production rate, which is an important factor of efficiency. The only possible way to estimate the filtration properties of the filter is to consider pressure values. In this study the pressure distribution in the filter was investigated in vitro. To explain the results and to calculate inaccessible parameters, a mathematical model was established which also considered the asymmetric behaviour of the filter membrane. The result was a linear pressure gradient, agreement with the measurements was reasonably good (calculated primary pressure loss differs <13% from measured value when using mean measured filter resistance as model parameter). Linear pressure distribution offers the possibility of easily calculating the filtration length, a parameter which can be used to estimate the filter condition. The comparison between calculated filtration and backfiltration rates offers an instrument of control for these values.

Adsorption↗