Volume Of Cell Suspension Research Articles

Separation of mast cells by centrifugal elutriation

Summary Mast cells can be separated from others in rat peritoneal washings by centrifugal elutriation with a purity comparable to that obtained by density gradient centrifugation. The principal of elutriation (countercurrent centrifugation) is to separate particles, having different sedimentation rates, suspended in a centripetal flow, balanced by the opposing centrifugal force. The yield of mast cells compared to the number in the original suspension was practically 100% under some conditions. An advantage of elutriation is that gradient material need not be removed from the fraction separated. The ability of the elutriation process to handle large volumes of cell suspensions in a continuous flow system would be advantageous for large-scale work.

An in vitro Test for Detection of Specific IgE-mediated Penicillin Reactions in Children

The diagnosis of untoward immediate hypersensitivity reactions to penicillin(s), thus far had to be amde presumptively on, at best, subjective clinical impression for lack of a simple, rapid, sensitive, reliable and reproducible in vitro immunological test. The objective of this work aims at fulfilling most of these criteria. Sera from 20 children clinically sensitive to penicillin and/or ampicillin, were incubated on a slide with a suspension of rat mast cells and various concentrations of penicillin, ampicillin, or penicilloyl-polylysine, under optimal conditions of pH and temperature. The cells were then examined microscopically for degranulation. A total number of 100 cells were counted over several randomly selected fields. The same model also was employed, using a monospecific goat antiserum to human myeloma IgE, instead of the specific drug. On incubation of equal volumes of cell suspension and serum from sensitive children, both the suspected drug and anti-IgE caused specific degranulation of the cells in a statiscally significant fashion : average number of degranulated cells in presence of sensitive sera and drug or anti-IgE was 3–4 times the number of altered cells in the absence of drug or anti-IgE, or in the presence of equivalent concentrations of anti-IgG, IgA, IgM. Control sera from nonsensitive matched children caused no significant degranulation. Or data indicate that : 1. This in vitro test can be used for rapid detection of penicillin-specific IgE antibodies. 2. Human IgE can sensitive rat cells in vitro, affording a test which may obviate skin testing for penicillin allergy in children.

Automated continuous culture of mammalian cells in suspension.

A system has been developed for the continuous culture of mammalian cells in suspension. The system maintains constant cell concentrations (monitored as the degree of light scattering) over a wide range of previously selected values by automatic additions of known amounts of medium and simultaneous withdrawals of equal volumes of cell suspension.

Growth Rate Measurements on Phytoplanktonic Organisms

as an index of growth are, by far, the most common, efficient and precise. Cell mass can be determined by measuring the increase in dry or fresh weight of cells and, for populations of microbial organisms, also by the estimation of the increase in the packed cell volume or in the turbidity caused by growing cells in a given volume of cell suspension. Other indices of growth, such as determinations of nitrogen, of the respiration rate, or of the accumulation of some products of cell metabolism (starch, acids, etc.), have been occasionally used in growth measurements. For the purpose of this paper the discussion will be directed to the laboratory study of plankton-often in pure culture. The interpretation of field responses will rest more and more on the understanding of the growth of marine species in pure culture. This is an essential step in providing a foundation for field studies where growth rate is more difficult to establish. Of all methods suitable for growth measurements of microbial populations, the turbidity technique is most convenient and expeditious. It also can be made most dependable. The basic advantage of the turbidity technique, in addition to its efficiency, is the possibility of taking repeated readings on the increase in turbidity of the same batch of the suspension of microbial cells. The same growth vessel, such as a test tube, containing a given volume of cell suspension, can be repeatedly taken out of the constant temperature bath (at specified intervals), subjected to turbidity measurements, and then returned to the bath. The time during which the growth vessel is out of the bath and, therefore, the interruption in conditions under which growth is observed, can be made minimal and its effect on the growth observations can be considered negligible. In estimations of other indices of growth, the cells subjected to observations are either killed, as in dry weight determinations, or affected unfavorably as to their capacity for subsequent growth, as in packed cell volume measurements. The destruction or damage to cells used for measurements makes it imperative either to limit observations on growth to just one determination of yield or, if measurements of the growth rate are intended, to rely in subsequent determinations on samples repeatedly withdrawn at intervals from the growth vessel. Sampling is an integral and a crucial element of all statistical investigations. The possibility of avoiding sampling by the turbidity technique saves time and increases the accuracy of growth measurements.

Disintegration of Microorganisms and Preparation of Yeast Cell Walls in a New Type of Disintegrator

Microbial cells were disintegrated in a new type of rotary disintegrator with a disc stirrer by a combination of shear force layers, collisions, and rolling of glass beads which were brought into motion by the stirrer. The rate of disintegration at a given dry bed volume of Ballotini beads and a given volume of cell suspension is proportional to the peripheral velocity of the stirrer up to 18 m/sec. Horizontal arrangement of the stirrer increases the effectiveness about five times; 100% disintegration of yeast cells was achieved under optimal conditions within 72 sec at a concentration of 3.5g (dry weight)/100 ml of suspension, and within 96 sec at a concentration of 10.5g (dry weight)/100ml. At 17.5 g (dry weight)/100 ml, the stirrer began to slip. The cell walls of yeast were obtained at the desired degree of crushing and the course of purification was determined by infrared spectral analysis.

Disintegration of Microorganisms and Preparation of Yeast Cell Walls in a New Type of Disintegrator

Microbial cells were disintegrated in a new type of rotary disintegrator with a disc stirrer by a combination of shear force layers, collisions, and rolling of glass beads which were brought into motion by the stirrer. The rate of disintegration at a given dry bed volume of Ballotini beads and a given volume of cell suspension is proportional to the peripheral velocity of the stirrer up to 18 m/sec. Horizontal arrangement of the stirrer increases the effectiveness about five times; 100% disintegration of yeast cells was achieved under optimal conditions within 72 sec at a concentration of 3.5g (dry weight)/100 ml of suspension, and within 96 sec at a concentration of 10.5g (dry weight)/100ml. At 17.5 g (dry weight)/100 ml, the stirrer began to slip. The cell walls of yeast were obtained at the desired degree of crushing and the course of purification was determined by infrared spectral analysis.