Baxter Travenol Laboratories, Inc.

Eugene K Achter

Rodolfo R Rodriguez

Paolo Priarone

Jerome C Kremen

Herbert Goldsmith

Michael B Uffer

David A Lohr

Carlton D Deaton

Horton E Dorman

An improved nephelometer for immunochemical complex assay measures forward light scatter in samples. The angle of forward scatter, about 30.degree., is small enough to result in a large amount of forward scatter from the immunochemical complex particles which are to be assayed, whose size is of the order of the wave length of the light used in the optical system. Forward scattering from smaller particles, such as from molecules of buffer, antibody and serum, is constant during the course of a test, and is compensated for by the use of subtraction circuits which are readily and semiautomatically adjusted to subtract proper values, in accordance with the readings taken on standard or 'blank' samples of buffer, antibody and serum. Forward scattering from large particles, such as dust, is variable, and results in fluctuating signals, which are electrically processed to ignore the spurious peaks. The results of a test are displayed on a digital read out meter. Also described is a method of and protocol for immunochemical assay, whereby the amount of antigen originally present in a sample is determined by adding a known amount of antibody, and by assaying the 'blank' component ingredients and the resulting mixture.

Nephelometer having means semiautomatically canceling components from

Nephelometer and nephelometer method for assaying immunochemical complex

A controller is disclosed for controlling the operation of selected electro-mechanical devices without the use of a microprocessor or similar computing machines. The controller includes a memory programmed to output a data word each time the memory is advanced to its next successive memory address. Responsive to the data word, an electro-mechanical device, identified by the data word, is actuated to perform its function. As the function of an electro-mechanical device is completed, a sensor develops a control signal for altering the internal count of a counter. The counter, in turn, advances the memory to its next address for outputting its next data word. The cycle continues as the memory is advanced through its addresses and selected electro-mechanical devices are successively actuated to perform their assigned functions.

Programmable controller

The modular chemical analysis system includes a first module or sample preparation apparatus for preparing sample solutions, a second module including a nephelometer apparatus comprising a stationary flow cell, mechanisms for moving sample solutions into and out of the flow cell, light generating means for passing light through the flow cell, electric circuitry for sensing the relative light scattered (R.L.S.) by the solution or particles in the solution in the flow cell and a third module comprising a microprocessing/calculator having a tape cartridge program. The microprocessor is coupled to the nephelometer apparatus (and, if desired, is also coupled to the sample preparation apparatus) for controlling operation of the nephelometer apparatus (and, if desired, to control the sample preparation apparatus). Also, the output from the nephelometer apparatus is coupled to the microprocessor which receives R.L.S. values and known concentration values for some solutions from which R.L.S. values were obtained. The microprocessor then calculates curve fit parameters for a polynomial regression curve equation, performs a Newton-Raphson inversion on the equation and calculated parameters to automatically calculate concentration values for R.L.S. values obtained from unknown test solutions thereby to obtain calculated concentration values from R.L.S. measurements.

Modular chemical analysis system

An apparatus and method for deriving an oxygen association curve for a blood sample wherein the sample is placed on a transparent support and is covered by a gas-permeable membrane element. The support is mounted in a gas treatment chamber with transparent windows on opposite sides of the support to provide an optical path through the support normal to the sample. Radiant energy is directed along this optical path, said radiant energy including two light frequencies, one having a wavelength at which there is substantially no change in absorbance as between oxygenated and deoxygenated blood and the other having a wavelength at which there is a relatively large change in absorbance as between oxygenated and deoxygenated blood. A controlled source of deoxygenating gas, such as nitrogen, and a controlled source of oxygen are connected to the chamber. An oxygen electrode is mounted in the chamber and generates the X component, corresponding to oxygen in the chamber, in an X-Y recorder. The difference in absorption of the two frequencies is measured and from this is derived a signal forming the Y component in the X-Y recorder, which thus provides a curve corresponding to the light absorbance changes in the sample while it is being oxygenated.

Method and apparatus for deriving oxygen association curves

An apparatus for incubating and analyzing blood samples while the samples are measured for oxygen association. The apparatus includes a controlled atmosphere chamber in which humidity, temperature and carbon dioxide may be maintained at a predetermined level while the level of oxygen concentration is varied. The samples are received in an apparatus which includes at least two slides having pockets therein for receiving the samples. The slides are arranged so that the specimens may be inserted in the holders, indexed to desired positions within the chamber for incubation and analysis, respectively, and removed from the chamber without affecting the controlled atmosphere within the chamber.

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Gaithersburg, MD, United States of America

Eugene K Achter