Coulter Counter Method Research Articles

Demonstration of a Non Osmotic Swelling and of a Three Step Mechanism During the Immune Lysis of Erythrocytes by Antibody and Complement

Abstract E to EAC1-9 cell intermediates were sized electrically with a hydrodynamic focusing system which is a modified Coulter counter method that avoids the methodologically right skewed volume distribution curves of the original method. No changes in the volume distribution curves of the erythrocytes were observed up to the EAC1-8 state. On addition of C9, a dose-dependent part of the cells did swell and three steps could be distinguished in the lytic mechanism: 1) fixation of C9 to EAC1-8 cells, a process which proceeds also well at 0°C; 2) a temperature-dependent swelling of the erythrocytes to their maximal volume in an all or nothing fashion; and 3) lysis of the cell. The swelling of the erythrocytes to spheroids is of a non-osmotic nature because it occurs also in highly concentrated 36% albumin solutions where the colloid osmotic forces of the intracellular protein are balanced on a molar basis. It persists into the ghost phase.

Experience in Adaptation and Comparative Evaluation of the Coulter Counter and Direct Microscopic Somatic Cell Count (DMSCC) Method for Determining Somatic Cell Counts in Milk

A Coulter Counter, Model ZBI, was introduced into a provincial government laboratory and adapted for use in counting somatic cells in milk. The procedure followed was a modification of the International Dairy Federation method, the main difference being in the formulation of the fixative and a slight change in diluent make-up. The procedure was further modified in operating details to enhance routine analytical work. During one year of use in the ongoing provincial laboratory program, 8130 milk samples were checked for somatic cells by the Coulter Counter. Of this number, 509 were selected at random and checked by the Direct Microscopic Somatic Cell Count (DMSCC) method. The correlation coefficient for these samples for the two methods was 0.973. The mean cell counts were 841.600 and 839,900 for the DMSCC and Coulter Counter methods, respectively. The regression formula for estimating DMSCC from Coulter Counter results was determined to be ŷ= 0.8023(x) + 163.45.

Stability of hydrocarbon-in-water emulsions during centrifugation. Influence of dispersed phase composition

The coalescence of emulsions of pure hydrocarbons in water stabilized by sodium dodecyl sulfate was studied during centrifugation in order to investigate the influence of composition of the dispersed phase on emulsion stability. The hydrocarbons used as the dispersed phase included nC 6 to nC 17 alkanes, benzene, and various n-alkylbenzenes. Emulsions containing equal volumes of hydrocarbon and aqueous phase were prepared using an aqueous solution of 8.0 × 10 −3 moles/liter of sodium dodecyl sulfate (the critical micelle concentration). The initial particle size of these emulsions was determined by microscopic observation, by the sodium alignate creaming method or by the Coulter counter method. A large fraction of the continuous aqueous phase was separated from the emulsion and all the hydrocarbon droplets were deformed into polyhedra very early during centrifugation. The mechanical stability of these emulsions was found to be dependent upon buoyant pressure, dispersed phase composition and properties and interfacial tension. Plots of φ, the fraction of stable emulsion remaining uncoagulated versus centrifugation time ( t) for n-C 17 to nC 8-in-water emulsions are fitted for all values of φ by the empirical equation φ = φ o t − n , where n varies from 0.14 to 0.17. The aromatic hydrocarbon-in-water emulsions showed a different behavior during centrifugation. These emulsions coagulated slowly during the first 20 min or more after which a drastic increase in coagulation rate was observed. The possible causes for the differences between n-alkane and aromatic emulsions behavior during centrifugation are discussed. The emulsion stability is inversely correlated with spreading coefficient of the hydrocarbon on the aqueous surfactant solution. Hydrocarbons with the most negative spreading coefficients produce the most stable emulsions.

Particle-Size Measurements by Coulter Counter of Very Small Deposits and Low Suspended Sediment Concentrations in Streams

ABSTRACT The Coulter Counter method of particle-size analysis, based on particle volume, is outlined. The method and associated procedures, previously used for soils, have particular use in particle-size analysis of fine sand and silt in quantities below the sensitivity of settling velocity and sieve methods. Schedules are presented here for pretreatment of samples and particle-size analysis by Coulter Counter. Application of the method is illustrated for particle-size analysis of individual sedimentary laminae, small features in soils, and suspended sediment in streams. Concentrations of suspended sediment recently reported for streams in eastern Australia are much lower than those generally published for the United States. The conventional methods used for particle-size analysis of the latte do not seem applicable where suspended sediment concentrations are low; the Coulter Counter method is an appropriate alternative.

Acridine Orange-Epifluorescence Technique for Counting Bacteria in Natural Waters

FRANCISCO, D. E., MAH, R. A. & RABIN, A. C. 1973. Acridine orange-epifluorescence technique for counting bacteria in natural waters. Trans. Amer. Micros. Soc., 92: 416-421. Total direct counts of aquatic bacteria from natural samples were estimated by epifluorescence microscopy after acridine orange staining. Cells were concentrated by membrane filtration on black membrane filters and counted directly. Using this method, bacterial counts of pure cultures corresponded to those obtained by the Petroff-Hauser and Coulter counter methods. Epifluorescence counting is the method of choice for ecological studies of the natural distribution of bacteria in aquatic environments since it permits ready discrimination of bacteria from detritus and does not rely on the adequacy of culture methods to elicit growth of all viable organisms. Total counts obtained in this way were related to glucose and acetate uptake by resident microbial populations of lake water sample. Viable counts of the same samples were not related.

Off-Axis Particles in Coulter Type Counters

The resistance increase due to a centered sphere in a tube traversed by an ideal fluid or electric current is tabulated in Phys. Fluids 7, 633 (1964). A lower limit for off-axis spheres is also known. This note gives an off-axis upper limit theory and a numerical table which should be useful in sizing particles by the Coulter counter method.

Size Analysis of Fine-grained Suspended Sediments: A Review

ABSTRACT Particle size analysis is one of the potentially most powerful tools available for the interpretation of any population of sedimentary particles. The size distribution characterizes the particles as a product, providing information on the actual particle sizes, and also is a prerequisite to understanding their roles in a set of sedimentary processes. Fine-grained suspended sediments are the least amenable to size analysis because of the difficulty of preserving the natural state of aggregation throughout sampling and analysis. Fine suspended sediments are composed of inorganic mineral matter and living and dead organic matter which occur as individual particles, and as agglomerates and aggregates. The projected areas, volumes, and diameters of the particles are highly variable as are their electrical and optical properties. The various methods of size analysis measure very different properties of the particle population. The basic methods of sizing fine suspended sediments described in this paper are microscopic analysis, optical-sedimentation analysis, direct optical analysis, and electronic (Coulter Counter) analysis. The microscopic method is the only one which permits direct visual observation of the particles, but yields a number frequency distribution rather than a weight or volume-size distribution. Optical-sedimentation methods permit analysis of the hydraulic behavior of the sediment in its natural medium, but at present are limited by concentration and size range. The Coulter Counter method is in some respects the most versatile method, but it yields a volume distribution which can not be directly related to settling velocity.

Investigations on starches from major starch crops grown in Ghana: III.—Particle size and particle size distribution

AbstractTwo procedures (sedimentation and Coulter counter) were used for the particle size analysis of starches from major West African starch crops. Data obtained by both methods appears to be in good agreement for large‐granule starches, e.g. large granule yam (Dioscorea) starches. The Coulter counter method, however, appears to be oversizing with starches having most of the granules smaller than 20 μm. This was also confirmed by microscopic examination accompanying the size analysis of all tested samples. Good agreement was found between the size analysis results on Dioscorea starches and some of their physical properties that were affected by granule size. To some extent, size and shape of Dioscorea starches can be used as a basis for differentiation even between cultivars; starches from different cultivars of plantain (Musa paradisiaca L.) and cassava (Manihot utilissima Pohl.) did not show any significant differences.

Certain Aspects of Production and Standing Stock of Particulate Matter in the Surface Waters of the Northwest Atlantic Ocean

Samples collected during January and October 1968 from 44° to 19°N in the western North Atlantic were analysed for particulate organic carbon, ATP, DNA, chlorophyll a, and total particulate volume between 1 and 40 μ diameter. Although the ratio of chlorophyll to ATP decreased from north to south, the ratio of particulate carbon to ATP did not show any systematic trend. A good correlation was found between ATP and DNA even though the DNA concentration was too great to be entirely representative of living material. Growth or production of particulate material as measured by the Coulter Counter method was higher than that measured by C-14 method. A trend was noted towards higher specific growth rate with smaller standing crop in southern waters.

A Comparison of Various Methods of Estimating Spermatozoa Concentration of Turkey Semen

SEVERAL methods have been used to estimate the spermatozoa concentration of chicken and turkey semen. Most of these methods involve actual spermatozoa counts (haemocytometer, Coulter counter), packed cell volume (hematocrit) or optical density (colorimeter, spectrophotometer).Jones and Wilson (1967) compared spermatozoa concentration of chicken semen obtained by the haemocytometer method with that determined electronically with a Coulter counter. They found that spermatozoa counts obtained with the Coulter counter were less variable and required less time. The coefficients of variation with the haemocytometer and Coulter counter methods were 10.2 and 2.7 percent respectively. There are no reports in the literature on the use of the Coulter counter for counting turkey spermatozoa.McCartney et al. (1958) and McCartney and Brown (1959) compared spermatozoa counts (haemocytometer) and packed cell volume of semen from small and large type white turkeys. McCartney et al. (1958) observed a highly significant correlation of +.67 between the values…

Membrane expansion of intact erythrocytes by anesthetics

1. 1. Low concentrations of the alcohol and phenothiazine anesthetics protected human erythrocytes from hypotonic hemolysis. 2. 2. The reduction in osmotic fragility amounted to a shift of 0.03 g/100 ml NaCl in the presence of a concentration of anesthetic which reduced osmotic hemolysis by 50 %. 3. 3. The anesthetics protected erythrocytes against hypotonic hemolysis over a 1000-fold range in the rate of hemolysis. The drugs do not act by changing the rate of hemolysis. 4. 4. Albumin up to 5.6 % did not reduce the amount of the osmotic hemolysis. Albumin did shift the dose-response curve for chlorpromazine to higher concentrations but only slightly reduced the maximum amount of protection. 5. 5. Low concentrations of the anesthetics did not affect the volumes of the cells in isotonic and moderately hypotonic solutions (down to 0.35 % NaCl). 6. 6. The critical hemolytic relative volume, V c, was measured by the Guest and Wing technique. The V c obtained by a Coulter counter and computer method agreed with the V c obtained using Van Allen hemotocrit tubes. The value for V c in the absence of any anesthetics was 1.825 and the membrane area of the prehemolytic sphere was about 136 μ 2. 7. 7. The anesthetics increased the V c. At an anesthetic concentration which reduced osmotic hemolysis by 50 %, the V c increased to 1.925; at 95 % reduction in hypotonic hemolysis the V c went up to around 2.02. The corresponding membrane areas were around 141 and 149 μ 2, respectively. at 50 % protection, therefore, the membrane area of the intact erythrocyte expanded by approx. 3 %.

Influence of Spray-Drying Conditions on Size and Size Distribution of Nonfat Dry Milk Particles

Particle size and size distribution of nonfat dry milk was determined by microscopic, sieve, and Coulter Counter methods. Data obtained by using the microscopic method indicated the smallest mean particle size, while data from the sieve method indicated the largest mean size. Results of the Coulter Counter method were changed slightly by the aperture size, but usually the curve was located between the results of the microscope and sieve.The distribution of particle size increased with an increase of total solids (30 to 50%) or a decrease in pump pressure (245 to 106 kg/cm2). Particle size was not significantly affected within the range of 121 to 177C inlet air temperature and 63 to 85C preheat treatment.An accurate evaluation of the particle size distribution of nonfat dry milk requires measurements by at least two methods: Coulter Counter and sieve or microscope methods.