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PubMed1996

Differences between super-centrifuged and membrane-filtrated soil solutions obtained from bulked and non-bulked topsoils by soil centrifugation.

The composition of the soil solution must be known to estimate the mobility and availability of plant nutrients and contaminants. When soil centrifugation is used to obtain the soil water for analysis, bulked soil samples are normally used in order to reduce random variations. In the present study, large systematic differences between the centrifugates from bulked and core samples are reported. For most of the soil solution components, no, or only small differences could be detected between super-centrifuged and membrane-filtrated solutions.

Journal Article↗
PubMed1993

A straight path centrifugal blood pump concept in the Capiox centrifugal pump.

This article describes comparative studies of a newly developed "straight path" centrifugal pump (Capiox centrifugal pump) targeted for open-heart surgery and circulatory support. A unique straight path design of the rotor was very effective in reducing the pump's rotational speed and prime volume. This pump was evaluated for hydraulics, hemolysis, depriming characteristics, cavitation, and heat generation. Two commercially available centrifugal pumps, the Biomedicus cone-type pump and the Sarns 3M impeller-type pump, were used as controls. The new pump required the lowest pump speed to produce the same flow rates under the same pressure loads and demonstrated the lowest hemolysis and the lowest temperature rise with the outlet clamped. The air volume required to deprime the new pump was one-third to one-half that for the other pumps, and no sign of cavitation was observed even if a small amount of air was introduced to the pump inlet under a negative pressure of 200 mm Hg.

Animals↗
PubMed2004

Current status of the gyro centrifugal blood pump--development of the permanently implantable centrifugal blood pump as a biventricular assist device (NEDO project).

The New Energy and Industrial Technology Development Organization (NEDO) project was started in 1995. The goal is the development of a multipurpose, totally implantable biventricular assist device (BVAD) that can be used for any patient who suffers from severe heart failure. Our C1E3 (two-week pump) centrifugal pump, called the Gyro pump, has three design characteristics: a magnetic coupling and double pivot bearing system, an eccentric inlet port, and secondary vanes on the bottom of the impeller. The pump was miniaturized. The C1E3 evolved into the NEDO PI-601, a totally implantable centrifugal pump for BVAD. The current NEDO PI-710 pump (five-year pump) system includes a centrifugal pump with pivot bearings, a hydraulically-levitated impeller, an rpm-controlled miniaturized actuator (all-in-one actuator plus controller), an emergency clamp on the left outflow, and a Frank-Starling-type flow control. The final mass production model is now finalized, and the final animal study and two-year endurance studies are ongoing.

Assisted Circulation↗
PubMed1985

Membrane characteristics and osmotic fragility of red cells, fractionated with anglehead centrifugation and counterflow centrifugation.

Red cell populations were separated on the basis of differences in density using anglehead centrifugation and on the basis of differences in mean cell volume using counterflow centrifugation. In the different fractions, mean surface area was calculated, phospholipid and cholesterol content determined as well as the osmotic behaviour in hypotonic salt solutions. Older red cells appeared to be more resistant to hypotonic salt solutions, due to favourable surface area to volume ratio.

Cell Separation↗
PubMed1984

Comparative responses of human polymorphonuclear leukocytes obtained by counterflow centrifugal elutriation and Ficoll-Hypaque density centrifugation. II. Membrane potential changes, membrane receptor analysis, membrane fluidity, and analysis of the effects of the preparative techniques.

Standard preparative techniques for human polymorphonuclear leukocytes involves the sequential exposure of the PMN to dextran, Ficoll-Hypaque (FH) gradient centrifugation, and hypotonic stress. Counterflow centrifugal elutriation (CCE) allows isolation of PMN from whole blood without exposure to these potentially toxic substances. We have previously reported that PMN isolated by CCE release more superoxide on stimulation than do PMN isolated by standard techniques (FH PMN). In this report, we extend these observations and show that CCE and FH PMN have similar binding kinetics for the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) and similar membrane fluidity. CCE PMN, however, were noted to have a more marked membrane depolarization on stimulation with FMLP than FH PMN. We show that exposure of purified CCE PMN to dextran increases their superoxide release on stimulation, as well as the available FMLP binding sites. Exposure of FH PMN to elutriation buffer increased their superoxide release on stimulation. It was also noted that both CCE and FH PMN re-exposed to FH increased available binding sites for FMLP. The possible reasons for these findings are discussed.

Adult↗
PubMed1983

The comparative responses of human polymorphonuclear leukocytes obtained by counterflow centrifugal elutriation and Ficoll-Hypaque density centrifugation. I. Resting volume, stimulus-induced superoxide production, and primary and specific granule release.

Standard isolation techniques for the human polymorphonuclear leukocyte (PMN) involve sequential exposure of cells to the nonphysiologic environments of dextran, Ficoll-Hypaque (FH) gradient centrifugation, and hypotonic conditions. It has been suggested that these may be harmful to the recovered PMN. Counterflow centrifugal elutriation (CCE) allows separation of human PMNs while the cells are continuously bathed in a physiologic and isotonic buffer. To investigate whether preparative technique may alter PMN activation, we compared PMNs obtained by these two methods for stimulus-induced superoxide production and release of primary and specific granule contents. Resting PMN volume was also evaluated. We observed that PMNs obtained using the CCE method were larger and released significantly more superoxide and specific granule contents than PMNs obtained by the standard FH technique. The possible origins for these differences are discussed.

Adult↗
PubMed1998

Isolation of intact organelles by differential centrifugation of digitonin-treated hepatocytes using a table Eppendorf centrifuge.

A quick subcellular fractionation procedure using differential centrifugation, which is applicable to isolated and cultured cells, is presented. This technique was developed for studying the subcellular localization of phosphorylated proteins in isolated liver cells after various stimuli, but is also applicable to many other situations. The main difference with the usual techniques is that by including digitonin in the homogenization buffer, the procedure is greatly shortened. Furthermore, because the soluble fraction is separated from the particulate fraction very early in the fractionation procedure, subcellular organelles are not exposed to phosphatases and other soluble enzymes such as esterases and proteases during the fractionation. The entire procedure is carried out in an Eppendorf centrifuge, which allows isolation of the cytosolic fraction in less than 1 min, a washed nuclear fraction in about 4 min, a mitochondrial fraction in less than 10 min, and a washed light mitochondrial L fraction in about 40 min. Judging by the behavior of marker enzymes and the morphology of the fractions, the method is highly comparable to classical procedures.

Animals↗
PubMed1983

A sectorial centrifuge cell for swinging bucket rotors--application to a velocity gradient centrifugation methodology.

A sectorial cell of 1.55 ml capacity, designed to be used in swinging bucket rotors, is introduced and applied to boundary sedimentation studies. The cell, made of polycarbonate by injection molding, represents an improvement over previously existing models in terms of resistance and attainable speeds. Its use has been extended to polydispersity determination by evaluation of the s value distribution function g(s) = dC/ds. The latter can be corrected to standard conditions (water at 20 degrees C), by using newly derived equations in connection with a cesium sulfate linear density and viscosity gradient which is introduced for boundary stabilization. The cell performance is illustrated with the centrifugal characterization of a polydisperse hyaluronate solution and a paucidisperse proteoglycan A1 preparation. In the latter case a distinctive distribution of aggregates into two polydisperse families of molecules, hitherto not reported in the literature but previously observed with cylindrical cells in this laboratory, has been clearly confirmed. Analysis of plateau dilution during centrifugation indicated absence of artifacts.

Centrifugation, Density Gradient↗
PubMed1993

Studies on a new cross-axis coil planet centrifuge for performing counter-current chromatography. II. Path and acceleration of coils and comparison with type J coil planet centrifuge.

A comprehensive approach is introduced using parametric equations to describe the motion induced by type J and cross-axis type coil planet centrifuges. The plots of a line parallel to the coil axis are given. The centrifugal forces are then analyzed in two ways. Three-dimensional graphs show their geometry and the relative intensity of the lateral component is compared to that of the perpendicular component. This allowed a better understanding of the differences in paths and acceleration fields induced by the two types of counter-current chromatography devices.

Acceleration↗
PubMed1988

Countercurrent centrifugal elutriation in a table-top centrifuge.

An elutriation system has been developed which fits into a small table-top centrifuge. The new CS1 rotor functioned as accurately as the JE-6 rotor, commercially available from Beckman Instruments. However, fewer cells were required for the separation experiments. Leukocytes obtained from 25 ml whole blood by Ficoll-Hypaque gradient centrifugation were sufficient for separating lymphocytes from monocytes and for purifying granulocytes. Furthermore, when lymphocytes were harvested from cell cultures 40 ml of a suspension of 1.2 x 10(6) cells/ml were enough to yield an enriched preparation of antibody producing cells.

Antibody-Producing Cells↗
PubMedDate not supplied

Human granulocyte isolation by continuous flow centrifugation leukapheresis and counterflow centrifugation elutriation (CFCL/CCE).

Human granulocytes (PMNL) isolated by continuous flow centrifugation leukapheresis (CFCL) were further purified by counterflow centrifugation elutriation (CCE). Studies were conducted to determine the maximal granulocyte capacity of the 4.5-ml elutriation chamber and to determine the efficiency of granulocyte recovery from CFCL concentrates. The maximal capacity of the elutriation chamber was determined to be 1.30 x 10(9) granulocytes with a 98.8 percent granulocyte purity and a 51:1 PMNL/RBC ratio. The efficiency of recovery was 82.2 percent with a 95.1 percent granulocyte purity and a 68:1 PMNL/RBC ratio. The CCE flow system was designed to allow continuous elutriation runs without need of breakdown time between runs. In four to five hours, approximately 4 to 5 x 10(9) granulocytes can be isolated with purity in excess of 95 percent. In vitro analysis of the viability and function of CFCL/CCE-isolated granulocytes indicates that the morphologic integrity and physiologic function were not comprised as a result of the combined isolation procedure relative to granulocytes isolated by CCE from whole blood samples. Granulocytes were held at 4 to 6 C for 16 to 24 hours in granulocyte storage medium (GSM) plus 20 percent autologous plasma at concentrations of about 6 x 10(6) PMNL/ml prior to in vitro analysis.

Blood Bactericidal Activity↗
PubMed1982

Coil planet centrifugal and capillary tube centrifugal analysis of factors regulating erythrocyte osmotic fragility and deformability.

Hydrated and dehydrated red cell samples were prepared from normal human red cells using the antibiotic nystatin. Furthermore, a series of red cell samples exposed to elevated temperature (20-50 degrees C, 10 min) were prepared. The osmotic fragility and deformability of these red cells were then measured, using the coil planet centrifuge system and the capillary tube centrifugal technique, respectively. The osmotic fragility of nystatin-treated red cells decreased and the deformability increased as dehydration of red cells progressed and alternatively, hydrated cells showed increased osmotic fragility and reduced deformability. Red cells exposed to elevated temperatures up to 49 degrees C for 10 min had no changes in mean corpuscular volume or in red cell shape. Above 47 degrees C, however, spectrin extractability progressively decreased and osmotic fragility and deformability decreased. Results suggest that the osmotic fragility snd deformability of red cells are interrelated, and are controlled by the geometry of the cell, including the ratio of cell surface area to cell volume and the viscoelastic properties of the membrane.

Centrifugation↗
PubMed1986

Xenobiotic metabolism in human alveolar type II cells isolated by centrifugal elutriation and density gradient centrifugation.

Alveolar type II cells were isolated from five human lung specimens obtained during resection or lobectomy and enriched to 63-85% purity. Digestion with Sigma protease type XIV followed by centrifugal elutriation and Percoll density gradient centrifugation yielded 1.2 +/- 0.4 X 10(6) cells/g lung in the type II cell fractions. The activities of some enzymes involved in the metabolism of xenobiotics were determined in these freshly isolated type II cells and compared with activities in alveolar macrophages and fractions of unseparated cells from the same tissue samples. Reduced nicotinamide adenine dinucleotide phosphate-cytochrome c reductase activity was similar in the three cell fractions from all five patients (18-29 nmol/mg protein/min). An antibody to rabbit reduced nicotinamide adenine dinucleotide phosphate-cytochrome P-450 reductase inhibited reduced nicotinamide adenine dinucleotide phosphate-cytochrome c reduction as much as 70% in microsomal preparations of the isolated human pulmonary cells, although this same antibody barely reacted with microsomes of the human cells in a Western blot assay. Epoxide hydrolase activity was highest in the alveolar type II cells (1.08 +/- 0.17 nmol/mg protein/min). This activity was 6 times higher than in the alveolar macrophage or unseparated cell fractions. 7-Ethoxycoumarin deethylase activity, a cytochrome P-450-dependent pathway, was low or undetectable in the three cell fractions. Trace amounts of 7-ethoxyresorufin O-deethylase activity (0.5-1.5 pmol/mg protein/min) were detected in microsomes of the isolated human cells, even though a polycyclic hydrocarbon-inducible cytochrome P-450 which metabolizes 7-ethoxyresorufin (form 6 in rabbits) was not detected immunochemically.

Adult↗
PubMed1976

[Isolation and function of platelets. I. Platelet rich plasma. Comparison between 2 methods: gel filtration and albumin density gradient centrifugation. II. A new method using total blood: metrizamide gradient centrifugation].

Human platelets separated from platelet rich plasma (PRP) by two different methods: gel filtraton and centrifugation on albumin gradient have been compared for yield, cellular and protein contamination, ultra-structure, platelet populations, shape change, aggregability and functional preservation. A new method for the separation of platelets from total blood on metrizamide gradients has been established. This technique is rapid and easy; it avoids the initial centrifugation of the PRP where about 30% of the platelets are lost and needs of blood 5 to 10 ml of blood.

Blood Platelets↗
PubMed1978

Granulocyte isolation by counterflow centrifugation-elutriation of canine blood obtained by continuous-flow centrifugation leukapheresis.

Granulocytes have been isolated by counterflow centrifugation-elutriation (CCE) from canine leukocyte-rich blood obtained by continuous-flow centrifugation leukapheresis (CFCL). We have attempted to define both the maximal granulocyte recovery and the efficiency of granulocyte purification for the Beckman JE6 elutriation rotor when large volumes of leukocyte rich blood are utilized. The efficiency of granulocyte purification by CCE is 81% (1.31 +/- 0.1 x 10(9) PMNL) if the number of granulocytes entered into the Beckman JE-6 rotor as leukocyte rich blood is limited to 1.60 +/- 0.13 x 10(9) PMNL. Approximately 96 +/- 2% of the leukocytes in the purified fraction were of the granulocytic series with mononuclear leukocytes comprising the residual 4% of the cell population. In vitro analysis of the isolated granulocytes indicated that the cells did not lose their morphological integrity or physiological function as a result of the dual CFCL/CCE procedure relative to granulocytes isolated by CCE from freshly drawn peripheral blood.

Animals↗
PubMed1977

[Thrombophoresis I. Influence of centrifuge speed on thrombocyte yield, distribution of thrombocytes among centrifuge zones, and thrombocyte spreading (author's transl)].

Thrombocyte yields up to 1,4 X 10(11) per litre of separated whole blood were obtained using centrifuge speed up to 2000 RPM. With increasing speed, higher platelet concentrations in the thrombocyte zone were accompanied by a progressive decline of thrombocyte counts in the plasma zone, whereas the thrombocyte contamination in the erythrocyte zone remained unchanged. Taking into account both high extraction efficiency and good preservation of platelet function as measured by Breddin's spreading test, optimal conditions for thrombophoresis with the Aminco Celltrifuge have been obtained at 1600 RPM. Since repeated separation of the donor's blood resulted in a rising number of platelets with impaired spreading capacity, the total blood flow should be limited to the blood volume of the donor.

Blood Cell Count↗
PubMed1976

Studies on new process procedures in plasma fractionation and industrial scale. III. Removal of precipitates by filtration through a horizontal leaf filter with centrifugal cleaning (Funda filter) as an alternative to tubular-bowl centrifuges.

The possibilities for replacing the time-consuming and labor-intensive centrifugation step in the plasma fractionation process with a filtration technique using filter aids were explored using a Funda filter (pat. Dr. Ing. Hans Müller). The filtration technique proved effective in the separation of the impure plasma fractions. On the other hand, its use in the separation of pure albumin and gamma-globulin fractions appears doubtful.

Centrifugation↗