Biomaterials, artificial cells, and immobilization biotechnology : official journal of the International Society for Artificial Cells and Immobilization Biotechnology最新文献

Microencapsulated genetically engineered E. coli cells can efficiently remove urea without any increase in the ammonia levels in the medium. A 100 mg. alginate encapsulated bacteria rapidly reduces urea in a 100 ml. solution. The original urea concentration 100.00 +/- 1.00 mg./dl. fell to 1.55 +/- 0.13 mg./dl. in 30 minutes. There was no increase in the ammonia in the reaction medium. Extrapolated results shows that urea depletion capacity of encapsulated bacteria is sufficient to remove urea during kidney failure. Using single pool model, 40 gm. of encapsulated genetically engineered E. coli can lower urea (100 mg./dl.) in 40 litres of the body water to 1.60 mg./dl. within 30 minutes. Also, 40.00 gm. bacteria can lower ammonia (758.00 microM/l), in 40 litres of body water, to 90.42 microM/l in 20 minutes. Further studies will be required for multi-compartmental models in the physiological conditions.

Combined use of plasma-exchange and dialysis therapy in 3 different cases of acute renal failure is presented. The first is a case of acute renal failure due to rhabdomyolysis caused by hemlock poisoning. Plasma-exchange was effective in improving the signs of rhabdomyolysis and renal failure. The second is a case of acute renal failure in an IgG-kappa myeloma. After 9 sessions of plasma-exchange, performed simultaneously with CAPD, a significant fall in the plasma and urine light chains levels was obtained. After the recovery of normal renal function, CAPD was prosecuted to remove light chains. The last is a case of acute renal failure in a patient with a mesangiocapillary nephritis and a high level of circulating immune complexes (CIC). He underwent steroid therapy and daily sessions of hemodialysis, followed by plasma-exchange, which permitted a fall of the CIC level, until a normal renal function was achieved. In conclusion, plasma-exchange combined with dialysis, is an useful tool for the management of acute renal failure caused by toxic proteins.

As a model surface, graphite slides were treated by pure nitrogen gas plasma for different periods (15 sec-5 min). These samples were kept in air or under argon atmosphere in sealed holders. STM images were obtained at constant current mode. Results showed that both the number and the size of clusters formed by plasma deposition increased with exposure time.

It is well known that red blood cell (RBC) and reticulocyte counts increase when anemic hemodialysis patients receive repeated administrations of recombinant human erythropoietin(rh-EPO). However, the early response of reticulocyte has not been reported precisely. In this study, reticulocyte counts and its fractions were observed in 8 maintenance hemodialysis patients after a single intravenous administration of 60 u/Kg of rh-EPO. The peripheral blood cells taken from the patients were stained with auramine 0, which bound to RNA and caused fluorescence. R-1000 (Sysmex, Kobe, Japan) analyzed the reticulocytes and classified the stained cells into three groups by the intensity of fluorescence. The number of highly fluorescent reticulocyte, which was young and large, increased and reached its highest level on day 4 after a single administration of rh-EPO. The reticulocyte counts paralleled these changes, but RBC counts did not change after administrations of rh-EPO. These data suggest that the observation of reticulocytes and its fractions in hemodialysis patients after a single administration of rh-EPO could tell us whether reticulocytes are responsive to rh-EPO or not, and this could be called as EPO test.

We tested the oxygen transport and delivery capacity of the novel perfluorocarbon emulsion, Therox (F44E, 1,2-bis-perfluorobutyl-ethylene) by comparing left ventricular regional and global function in dogs during perfusion of the left anterior descending coronary artery (LAD) with oxygenated Krebs buffer and oxygenated Therox emulsion (20% w/v) at 20 ml/min for two separate 3 min periods. During LAD perfusion with oxygenated Krebs buffer, complete loss of systolic wall thickening in the LAD perfusion area was observed, dP/dt was significantly reduced and left ventricular end-diastolic pressure (LVEDP) was increased. In contrast, LAD perfusion with oxygenated Therox maintained regional wall thickening at 60-70% of control and completely preserved global function as measured by dP/dt and LVEDP. Thus, Therox is an effective oxygen carrier in this animal model.

Aminoacylase I (E.C.3.5.1.14) was immobilized by entrapment in calcium alginate beads coated with polyethyleneimine for the production of L-phenylalanine by the hydrolysis of a racemic mixture of N-acetyl-DL-phenylalanine. The operational stability in terms of batch operation and continuous reaction in packed-bed bioreactor were studied. Kinetic constants, Km and Vmax values of free and immobilized enzymes were studied. Polyethyleneimine treatment was found to enhance the operational stability of the enzyme though its activity was substantially reduced. When polyethyleneimine-coated calcium alginate beads were packed into packed bed bioreactor, it was stable for at least 25 days under continuous operation without appreciable loss of activity.

In order to evaluate the possibility to administer high FUDR doses, 52 patients with liver metastases were treated with loco-regional chemotherapy associated with venous hemofiltration. The clinical and pharmacological results of this approach are discussed.

In summary the therapeutic use of affinity chromatography, the immunapheresis with LDL-Therasorb columns, Baxter, has been shown to be a safe, specific and efficacious extracorporeal treatment. Following GMP rules LDL-Therasorb is produced in a constant quality. Beyond the treatment of hypercholesterolemia the versatility of antibodies opens this technology to the treatment of other diseases.

The administration of high doses of Methotrexate (HDMTX) seems to be very effective in neoplastic treatment. Furthermore high doses of the drug could overcome the Methotrexate (MTX) resistance that it is possible to observe in some kind of cancers. To avoid several serious problems in the therapeutical application of HDMTX such as nephrotoxicity, hepatotoxicity and the difficulty to assess the right therapeutic range of the specific antagonist Leucovorin, a Haemoperfusion (HP) treatment could be very usefulL. In this study 3 anion exchange resins with different active group (trimethylammonium, dimethylethanolammonium and dimethylammina) and a spherical petroleum based charcoal were tested both in vitro and ex vivo to evaluate their capability to remove MTX. These results show a good strength and biocompatibility of the 4 sorbents and demonstrate the active group trimethylammonium resin as the most effective one.

Process parameters using a Microfluidizer M110 to produce liposome-encapsulated hemoglobin (LEH) were further studied to examine their effect on hemoglobin (Hb) encapsulation efficiency (yield), steady shear viscosity, mechanical stability, and oxygen delivery. Liposome formulation loading ratios of up to 300 mumol of lipid per ml of Hb solution were evaluated; a maximum yield was obtained at 300 mumol/ml. Liposomes containing encapsulated Hb concentrations as high as 15.5 g/100 ml were prepared. LEH particle size distribution, determined from negatively stained whole mount preparations using transmission electron microscopy, resulted in average vesicle sizes for optimal batches of about 155 nm. Steady shear viscosity of LEH (up to 40% by volume) in an isotonic-isooncotic solution of PBS containing either albumin or dextran were evaluated for shear rates to 2000 s-1. Values obtained were generally higher than those of whole blood at all shear rates tested. Little leakage of Hb from liposomes stored in isotonic PBS was observed as a function of storage time and shear rate. Administration of LEH supported life in rats whose hematocrit had been reduced via isovolemic exchange transfusion to levels well below 5%, which was incompatible with survival when exchange transfusion was performed with the isotonic-isooncotic PBS solution.