[Acute abdominal pain in a 19-year-old patient taking oral contraceptives].
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Abdomen, Acute↗
Biomedical subjects
T Bosch
Publications and source records attributed to T Bosch.
DALI apheresis in hyperlipidemic patients: biocompatibility, efficacy, and selectivity of direct adsorption of lipoproteins from whole blood.
Recently, the first apheresis technique for direct adsorption of low-density lipoprotein (LDL) and lipoprotein(a) [Lp(a)] from whole blood (DALI) was developed that does not require a prior plasma separation. That markedly simplifies the extracorporeal circuit. The aim of the present study was to test the acute biocompatibility, efficacy, and selectivity of DALI apheresis. In a prospective clinical study, 6 hypercholesterolemic patients suffering from angiographically proven atherosclerosis were treated 4 times each by DALI. 1.3 patient blood volumes were treated per session at blood flow rates of 60-80 ml/min using 750 or 1,000 ml of polyacrylate/polyacrylamide adsorber gel. The anticoagulation consisted of an initial heparin bolus followed by a citrate infusion. The sessions were clinically essentially uneventful. Mean corrected reductions of lipoproteins amounted to 65% for LDL-cholesterol, 54% for Lp(a), 28% for triglycerides, 1% for HDL-cholesterol, and 8% for fibrinogen. The selectivity of lipoprotein removal was high. Cell counts remained virtually unchanged and no signs of hemolysis or clotting were detected. Cell activation parameters elastase, beta-thromboglobulin, interleukin-1beta, and IL-6 showed no significant increase. Complement activation was negligible. There was significant, but clinically asymptomatic, bradykinin activation in the adsorber with mean maxima of 12,000 pg/ml in the efferent line at 1,000 ml of treated blood volume. In conclusion, DALI proved to be safe, selective, and efficient for the adsorption of LDL-C and Lp(a), which simplifies substantially the extracorporeal therapy in hypercholesterolemic patients.
Acrylic Resins↗
Ex vivo biocompatibility of avidin-agarose: a new device for direct adsorption of biotinylated antibodies from human whole blood.
Radioimmunotherapy using radiolabeled antitumor antibodies (RAA) is limited by the toxicity of unbound antibodies in the circulation. Removal of excessive antibodies by affinity-adsorption could therefore allow the administration of increased dosages of RAA while decreasing their adverse effects. Recently, avidin-agarose (AA) minicolumns were used in animal experiments for the removal of biotinylated antibodies from whole blood exploiting the high affinity binding of biotin to avidin (pK 1015 M-1). This study was performed to evaluate the ex vivo biocompatibility of AA minicolumns with human blood. Ten ml AA minicolumns were perfused online ex vivo in the single pass mode with fresh blood from 8 healthy donors at a flow rate of 6.25 ml/min. The anticoagulation consisted of 0.5 IU heparin plus 0.0-2.1 mg citrate per ml of blood. In Part 1 of the study (40 min perfusion, n = 4), the optimal anticoagulation was found to be 0.5 IU heparin plus about 1 mg citrate per ml of blood. In Part 2 of the study, four 80 min test-runs were performed. No signs of hemolysis were found, and the thrombogenicity of the AA gel was negligible. Cell counts and column inlet pressures remained constant; toward the end of the 80 min test-runs, some activation of blood cells (elastase, beta-thromboglobulin), the complement system (C3a, C5a) and the plasmatic coagulation (thrombin-antithrombin complex) was detectable. A moderate initial bradykinin release rapidly subsided to very low levels. In summary, AA minicolumns showed good biocompatibility upon contact with human whole blood and merit further investigation in a closed-loop system for a potential application of direct tumor antibody removal by hemoperfusion.
Adsorption↗
Effect of low-dose citrate anticoagulation on the clinical safety and efficacy of direct adsorption of lipoproteins (DALI apheresis) in hypercholesterolemic patients: a prospective controlled clinical trial.
Direct adsorption of lipoproteins (DALI) is the first lipid apheresis system compatible with whole blood with the advantage of a very simple procedure. A mixture of heparin plus citrate (ACD-A) is used for the anticoagulation regimen (AR). A clinical, prospective, controlled crossover study was performed to test the safety and efficacy of low-dose citrate (LDC) anticoagulation in DALI. Five chronic DALI patients suffering from coronary heart disease and hypercholesterolemia underwent 3 DALI sessions each using the LDC anticoagulation regimen (60 IU heparin/kg body weight as initial bolus; 1:40 ACD-A: blood as perfusion). This was compared to 3 sessions per patient with the standard AR (bolus of 20 IU heparin/kg, 1:20 ACD-A as perfusion). Patient blood volumes (1.6; average of 7,040 ml) were treated with 750 ml adsorber gel per session at a blood flow rate of 60 ml/min. Mean LDL and Lp(a) reductions exceeded 60% with both AR. No clinical side effects were observed. Both AR controlled the coagulation well as evidenced by a sufficient prolongation of the partial prothrombin time (PTT) and activated clotting time as well as low thrombin-antithrombin (TAT) formation. Biocompatibility parameters exhibited favorable results (low activation of complement and cells, and only slight formation of C3a, C5a, beta-thromboglobulin, elastase, and TNF-alpha). The asymptomatic bradykinin generation was comparable in both study arms. LDC optimized the ionized calcium levels and pH in the efferent blood postadsorber. LDC anticoagulation was safe and effective, and may further improve the tolerance of DALI apheresis in hypercholesterolemic patients.
Adsorption↗
Immunoadsorption, current status and future developments.
The association of abnormalities in the cellular and humoral immune system with various autoimmune diseases provides the rationale for apheresis technologies. While plasmapheresis or plasma exchange is limited by its non-selective removal of all plasma components, modern apheresis techniques aim to provide more specific elimination according to clinical needs and avoid plasma product replacement. However, the commercialisation has not met the expectations in the early 80's and the number of patients treated by extracorporeal immunoadsorption remains small due to a lack of well-defined controlled trials and limited reimbursement. This review highlights the immunological and technical basis for extracorporeal immunoadsorption, as well as its current status in the treatment of immunologically-mediated diseases.
Animals↗
Evaluation of microparticle leakage during DALI LDL adsorption in a simulated clinical setting.
The aim of the present study was to investigate microparticle (Mp) leakage during simulated LDL-hemoperfusion using 12 DALI 750 adsorbers and the original DALI hardware under conditions strictly comparable to the clinical situation. Thus, the sessions were divided into 4 sections, i.e. priming and preparation of the adsorber followed by treatment (6-7 L at a flow rate of 60 ml/min) and reinfusion. As Mp counts can be performed only in clear, cell-free media, blood was replaced by normal saline in sections 2-4 of the simulated sessions. Mp counts were analysed for > or = 2, > or = 5, > or = 10 and > or = 25 microm particle sizes in the efferent line post adsorber using a standard light blockage method. As there are no official thresholds for particle release in extracorporeal circuits, the limits for infusion of large fluid volumes of 500, 100 (80), 25 and 5 (3) Mp/ml according to the Europäische Arzneimittelbuch, the British and American Pharmacopoeias were used. Mean particle counts for the sections 3 and 4 in which the patient is connected to the efferent line were 19, 7, 2 and 0 Mp/ml and amounted to < 10% of the above mentioned limits. Modifications of the standard simulation procedure by inserting additional pump stops or using different flow rates during the treatment phase slightly increased Mp leakage, but never exceeded the prescribed limits. In summary, no undue particle release could be detected during simulations of the clinical DALI LDL-adsorption procedure.
Adsorption↗
Heparin-free DALI LDL-apheresis in hyperlipidemic patients: efficacy, safety and biocompatibility.
BACKGROUND AND AIM OF STUDY: In routine DALI apheresis--the first technique for direct adsorption of lipoproteins from whole blood--heparin plus citrate (ACD-A) is used as anticoagulation regimen. However, recently several publications have warned of heparin-induced thrombocytopenia as a rare but potentially life-threatening complication of heparin administration (HIT type 2). The aim of the present study was therefore to test the efficacy and biocompatibility of DALI using a heparin-free anticoagulation regimen consisting exclusively of citrate. METHODS: Four symptomatic hypercholesterolemic patients on regular DALI apheresis were switched to the heparin-free protocol for two sessions each. Two of the patients were on oral anticoagulation using phenprocoumon. In the weekly sessions, 1.3 patient blood volumes were processed at a blood flow rate of 60 ml/min using ACD-A at a ratio of 1:20 (v/v) during adsorber priming and the session. RESULTS: Clinically, all sessions were essentially uneventful. Uncorrected lipoprotein reductions amounted to 65% for LDL-C, 62% for Lp(a), 53% for VLDL-C, 24% for HDL-C, 17% for triglycerides and 19% for fibrinogen. Cell counts remained virtually constant. No signs of hemolysis or clotting could be detected. Thromboplastin time (Quick) was slightly prolonged and partial thromboplastin time (PTT) moderately elevated in all patients. In contrast, whole blood coagulation time acc. to Lee-White and activated clotting times were increased only in orally anticoagulated patients. Biocompatibility in terms of complement, leukocyte and thrombocyte activation was excellent. Bradykinin activation was moderate peaking at 3038 pg/ml in the efferent line. Systemic thrombin-antithrombin complex (TAT) reflected perfect anticoagulation in orally anticoagulated patients and adequate anticoagulation in the patients without phenprocoumon. CONCLUSION: In this pilot study, heparin-free DALI apheresis was safe and effective and may thus be performed in LDL-apheresis dependent patients who suffer from heparin intolerance.
Adsorption↗
Therapeutic plasma exchange in patients with chylomicronemia syndrome complicated by acute pancreatitis.
Chylomicronemia syndrome (CMS) is a rare disorder characterized by the presence of chylomicrons in the fasting state causing a milky appearance of plasma, eruptive xanthomas, and hepatosplenomegaly; an acute and potentially life threatening complication is severe acute pancreatitis. The underlying defects are inborn errors of metabolism such as deficiencies of lipoprotein lipase (LPL) or apoprotein C-II (apo C-II) as well as familial hypertriglyceridemia. Moreover, CMS can be precipitated when mild hypertriglyceridemia is exacerbated by additional factors such diabetes mellitus, ethanol abuse, or pregnancy. The purpose of the present study was to retrospectively analyze the results of therapeutic plasma exchange (TPE) in 5 patients transferred to our hospital for severe acute pancreatitis due to chylomicronemia syndrome. In a total of 7 TPE sessions, on average 3,286 +/- 247 ml of plasma (i.e., about 1 patient plasma volume) were treated per session. Triglyceride (TG) levels were decreased from 4,972 +/- 2,469 mg/dl on admission to 1,614 +/- 1,276 mg/dl (-70%) after the TPE sessions, and a further decrease was achieved by conservative treatment. Part of the TG reducing effect of the treatment was probably due to heparin induced lipolysis. Acute pancreatitis was resolved in all cases, and 1 pregnant patient delivered without problems at term. In summary, 1 or 2 TPE sessions sufficed to substantially decrease the bulk of triglycerides in acutely exacerbated chylomicronemia syndrome causing a rapid resolution of acute severe pancreatitis.
Acute Disease↗
Low density lipoprotein hemoperfusion by direct adsorption of lipoproteins from whole blood (DALI apheresis): clinical experience from a single center.
The elimination of low density lipoprotein (LDL) and lipoprotein (a) (Lp[a]) by conventional LDL apheresis techniques can only be achieved in a cell-free medium and thus requires the initial separation of plasma from the blood cells. The present paper describes the first LDL hemoperfusion system which is able to adsorb LDL and Lp(a) directly from whole blood. This simplifies the procedure substantially. The adsorber consists of polyacrylate ligands linked to a modified polyacrylamide matrix. These negatively charged polyacrylate ligands interact with the positively charged apoprotein B moiety of LDL and Lp(a), which results in selective adsorption of these lipoproteins onto the column. Three hypercholesterolemic patients suffering from overt atherosclerotic complications were treated weekly by direct adsorption of lipoproteins (DALI) (n = 20 sessions each). All patients were on the highest tolerated dose of cholesterol synthesis enzyme (CSE) inhibitors. About 1.3 patient blood volumes were treated per session. The anticoagulation was performed with acid citrate dextrose (ACD-A). The following acute reductions were achieved: LDL: 66%; Lp(a): 63%; and triglycerides: 29%. High density lipoprotein (HDL) (-13%) and fibrinogen (-16%) were not substantially reduced. The sessions were essentially uneventful. Due to a low ACD-A infusion rate, no hypocalcemic episodes were registered. One patient on enalapril was treated without complications when this angiotensin converting enzyme (ACE) inhibitor was withdrawn 2 days prior to apheresis. In summary, in our hands, DALI apheresis proved to be a simple, safe, and efficient method of lipid apheresis in hypercholesterolemic patients refractory to conservative lipid lowering therapy.
Adsorption↗
Therapeutic plasma exchange in patients suffering from thrombotic microangiopathy after allogeneic bone marrow transplantation.
Thrombotic microangiopathy (TM) is a potentially fatal complication of allogeneic bone marrow transplantation (BMT). The underlying pathophysiology is thought to be generalized endothelial cell damage caused by several factors including conditioning treatment, cyclosporin A (CsA), or graft versus host disease (GVHD). In the present retrospective study, 6 patients suffering from Grade 2 BMT-TM at a mean of 62 days post BMT were treated by 3-15 daily sessions of therapeutic plasma exchange (TPE). In most sessions, cryosupernatant (CSN) of plasma, in some fresh frozen plasma (FFP) was used as the substitution fluid. All patients suffered from acute graft versus host disease (aGVHD) of the skin, which was treated by CsA. CsA was withdrawn in all patients. TPE caused a response in 4 of 6 patients evidenced by a decrease to Grade 0 (n = 3) or 1 (n = 1) BMT-TM. Only 1 patient had mild renal insufficiency which did not improve during TPE. While all patients were dependent on platelet transfusions at baseline, the platelet counts improved in 2 of 6 patients after the TPE course. One patient did not show any response to TPE with FFP, and his disease improved only after CSN was introduced as substitution fluid (Grade 0). Four patients were still alive 175-495 days post BMT, and 2 patients died about 2-3 weeks after the end of the TPE course, 1 from cachexia and 1 from systemic aspergillosis. In summary, in this pilot study, TPE positively influenced BMT-TM, especially if CSN was used as the substitution fluid.
Adult↗
State of the art of therapeutic apheresis in Europe.
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Blood Component Removal↗
A simultaneous study of the metabolism of apolipoprotein B and albumin in nephrotic patients.
BACKGROUND: The nephrotic syndrome is characterized by proteinuria, hypoalbuminemia and hyperlipidemia. Despite intensive research it is not clear at present what the causal links are between these pathological findings. METHODS: Stable isotope labeled amino acid tracer kinetic analysis was used to simultaneously investigate the metabolism of four apolipoprotein B-containing lipoproteins (VLDL1, VLDL2, IDL and LDL) and albumin in seven patients with nephrotic syndrome and marked hypercholesterolemia, in two additional nephrotic patients with concomitant renal failure and mixed hyperlipidemia, and in a matched group of normolipidemic controls. RESULTS: Increased concentrations of VLDL2, IDL and LDL were due to (a) impaired VLDL2 and IDL delipidation, (b) reduced LDL catabolism, and (c) a trend towards an increased rate of total apolipoprotein B production. The rate of fractional albumin elimination was three times higher in patients than in controls and the rate of albumin synthesis was increased by 45%. No correlations were detectable between rates of apolipoprotein B production and the rate of albumin synthesis. CONCLUSIONS: The results of this study suggest that hyperlipidemia in nephrotic syndrome is predominantly the result of delayed lipoprotein delipidation and catabolism. There is no evidence that it is driven by a general increase of the rate of hepatic protein synthesis.
Adult↗
LDL hemoperfusion--a new procedure for LDL apheresis: biocompatibility results from a first pilot study in hypercholesterolemic atherosclerosis patients.
Current lipid apheresis techniques can remove atherogenic lipoproteins only from plasma. The initial mandatory separation of plasma and blood cells renders the extracorporeal circuit complex. We recently described the first clinical application of a new lipid adsorber that adsorbs low-density lipoprotein (LDL) and lipoprotein (a) (Lp[a]) directly from whole blood. In continuation of our work, this paper describes the clinical biocompatibility of this new LDL hemoperfusion system. In a 2 center phase II clinical trial, 12 hypercholesterolemic patients suffering from overt coronary or peripheral artery disease were treated once with LDL hemoperfusion. The new LDL adsorber (DALI, Fresenius, St. Wendel, Germany) contained 480 ml of polyacrylate coated polyacrylamide gel. The anticoagulation protocol consisted of an initial heparin bolus followed by an acid citrate dextrose-A (ACD-A) infusion during the treatment. One patient blood volume was treated per session. All sessions were clinically uneventful. No signs of hemolysis or extracorporeal clot formation could be detected, and cell counts remained virtually constant. In a subgroup of patients (n = 4-6), further biocompatibility parameters were studied. Activation of leukocytes (elastase release), thrombocytes (beta-thromboglobulin [beta-TG] extrusion), and monocytes (interleukin (IL)-1beta and IL-6) were minimal. Complement activation (C3a and C5a generation) was negligible. The chosen anticoagulation protocol was both safe (constant ionized calcium levels) and effective (low thrombin-antithrombin formation). In summary, within the scope of a first pilot study, this new LDL hemoperfusion procedure combined the features of excellent clinical tolerance, good biocompatibility, and ease of handling. Phase III clinical trials will have to show whether these encouraging preliminary results can be corroborated in a larger patient population.
Acrylic Resins↗
LDL hemoperfusion--a new procedure for LDL apheresis: first clinical application of an LDL adsorber compatible with human whole blood.
To date, lipid apheresis procedures can remove low-density lipoprotein (LDL) cholesterol (LDL-C) only from plasma. Thus, initially plasma has to be separated from the blood cells, which increases the costs and complexity of the extracorporeal circuit. This paper describes the first clinical application of a new LDL adsorber that eliminates LDL directly from whole blood. The goal of this pilot study was to test the efficacy, safety, and feasibility of direct lipoprotein adsorption in patients. In a 2 center Phase II clinical trial, 12 hypercholesterolemic patients suffering from overt coronary or peripheral artery disease were treated once with LDL hemoperfusion. The new LDL adsorber (DALI, Fresenius, St. Wendel, Germany) contained 480 ml of polyacrylate coated polyacrylamide gel. The anticoagulation consisted of an initial heparin bolus followed by an acid citrate dextrose (ACD)-A infusion during the treatment. The processing of nearly 1 patient blood volume resulted in a reduction of LDL-C by 45 +/- 8% and triglycerides by 23 +/- 20%. HDL-C, fibrinogen, and cell counts were not significantly influenced. In a subgroup of 5 patients who exhibited elevated lipoprotein (a) (Lp[a]) levels, Lp(a) reduction was 43 +/- 15% (all results corrected for plasma volume shifts). The sessions were clinically uneventful; the system was technically safe and easily handled. In conclusion, short-term LDL hemoperfusion by the DALI proved to be a safe, effective, and simple procedure for the treatment of patients suffering from symptomatic recalcitrant hypercholesterolemia. The present study represents a solid basis for the clinical long-term evaluation of this new technique in the future.
Acrylic Resins↗
State of the art of lipid apheresis.
Currently, 5 different lipid apheresis procedures are available for routine clinical treatment of hypercholesterolemic patients. Unselective plasma exchange is a technically simple extracorporeal circuit, but albumin substitution fluid must be used and there is no high-density lipoprotein (HDL) recovery. Semiselective double filtration with improved size selectivity because of a small-pore secondary filter combines good elimination of low-density lipoprotein (LDL), lipoprotein (a) (Lp[a]), and fibrinogen with adequate HDL recovery; modifications such as thermofiltration, predilution/backflush, or pulsatile flow have been proposed for the improvement of this system. Three highly selective procedures are based on immunologic or electrostatic interactions: immunoadsorption using anti-low-density lipoprotein (LDL) antibodies, chemoadsorption onto dextran sulfate, and heparin-induced LDL precipitation (HELP) apheresis. The features of each system are discussed critically. Lastly, two new developments, Lp(a) immunoadsorption and LDL hemoperfusion using a polyacrylate LDL adsorber compatible with whole blood, are described.
Antibodies↗
Low-density lipoprotein hemoperfusion using a modified polyacrylate adsorber: in vitro, ex vivo, and first clinical results.
Current lipid apheresis techniques can remove low-density lipoprotein (LDL) cholesterol only from plasma, i.e., a primary cell-plasma separation step is mandatory. This article describes in vitro, ex vivo, and clinical results using a new LDL adsorber compatible with human whole blood. It consists of modified polyacrylate, the negative charges of which can interact with the positively charged protein B moiety of LDL, thus retaining these particles on the surface of the adsorber. After the efficacy and selectivity of LDL removal had been demonstrated in vitro and ex vivo, a clinical pilot study corroborated these results. Thus, treating 60 ml of blood per kilogram of body weight in a single session, LDL hemoperfusion reduced LDL cholesterol by 50%, lipoprotein (a) by 17%, and triglycerides by 19% in 6 hypercholesterolemic patients. High-density lipoprotein cholesterol recovery amounted to 97%. In conclusion, LDL hemoperfusion holds great promise for the future.
Acrylic Resins↗
Plasma therapy at Klinikum Grosshadern: a 15-year retrospective.
Immediately after the availability of highly permeable membranes in 1979, membrane plasma separation was introduced as a mode of extracorporeal blood purification by the nephrology group at Klinikum Grosshadern of the Ludwig Maximilians University of Munich (F.R.G.). The new therapy was applied primarily in the management of immunologically mediated renal and extrarenal disorders as well as in paraproteinemias. We also have witnessed a widespread application of this extracorporeal treatment as a last resort in otherwise refractory clinical conditions. Over the years, the group at Grosshadern has contributed to the development, as well as to the laboratory and clinical testing, of new plasma separation membranes, simplified plasmapheresis formats (e.g., spontaneous membrane plasma separation), and several plasma fractionation procedures (e.g., cascade filtration, adsorption). Whenever indicated and possible, plasma fractionation procedures, rather than unselective plasma exchange, are performed in an appropriate clinical situation.
Chemical Fractionation↗
Lipid apheresis: from a heroic treatment to routine clinical practice.
Lipid apheresis has developed from a heroic treatment into a routine clinical therapy and currently is the major indication for performing extracorporeal plasma therapy. Whereas it was once reserved for patients with homozygous familial hypercholesterolemia, today it has a place in the secondary prevention of severe coronary heart disease when low-density lipoprotein (LDL)-cholesterol level exceeds 150 mg/dl, despite conservative treatment, in any type of primary hypercholesterolemia. Unselective plasma exchange has been replaced by a variety of selective procedures. The efficacy of the treatment can be maximized by combining LDL apheresis with the use of cholesterol synthesis enzyme inhibitors. Clinical studies have shown that drastic cholesterol reduction can result in regression of coronary atherosclerosis as well as in reduced cardiac morbidity and mortality. Technical progress comprises improved selectivity, online regeneration of adsorbers, and LDL adsorption from whole blood. Recently, a new LDL hemoperfusion procedure was successfully tested in a clinical pilot study; blood is passed directly over a lipid sorbent without prior plasma separation. If this system is demonstrated to be safe and effective in clinical Phase III trials, a further qualitative step in the rapid development of LDL apheresis will have made.
Adsorption↗