Abstract: A technique for measuring the degree of an antigen-antibody reaction by preparing a suspension of insoluble microscopic carrier particles of at least one type carrying an antigen, an antibody or a hapten, forming an agglutination promoting or inhibiting reaction system among the insoluble carrier particles based on an antigen-antibody reaction using the suspension and one or more antigen, antibody or hapten, irradiating the solution of the reaction system with laser light and detecting the light scattered from the reaction system at one or more specific angles, detecting a signal indicative of one or more specific frequency bands from the resulting scatter spectrum, and thenceforth calculating the quantity of antigen, antibody or hapten in a specimen on the basis of the detected signal. The intensity spectrum output of filter 11 for frequency band selection is in the form of a square root and is converted into the original intensity spectrum by means of a squaring circuit 12.

Abstract: An apparatus for taking up and discharging liquid has at least one piston cylinder which responds to a command by taking up or discharging liquid, the arrangement being such that the number of liquid uptake operations is preset, with the piston cylinder being instructed to perform the discharge operation when the number of uptake operations actually performed is detected to exceed said preset number. A plurality of different liquid specimens can be mixed, and the mixture diluted when so desired, through a simple operation which assures great accuracy.

Abstract: A laser nephelometric system measures the concentration of various substances in a solution particularly in blood or serum. The system receives a number of data elements each indicative of the intensity of light scattered from the solution at its sampling time. These data elements are processed in accordance with a statistical analysis. Based upon the fact that the relative variation of the scattered light intensity increases as the scattered light decreases, a first screening of data elements is performed so that the band of selection for data elements accords with the above fact. Further a second screening of data elements is performed in order to reduce the effect of the unnecessary light resulting from the other reflecting objects, such as dust, air bubbles and other substances. The average of the screened data elements provides an accurate value of the intensity of scattered light due to the substances to be measured, i.e. measurand.

Abstract: An aminobenzoic acid derivative represented by the formula ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are defined hereinbelow, which has excellent activity for improving liver function and for potentiating and normalizing immunity; a process for preparing the same; and a pharmaceutical composition containing the same are disclosed.

Abstract: A method for the quantitative determination of antigenic substance without any confirmation test which comprises adding to a sample to be assayed an exogenous antigenic substance in a certain amount, combining the resulting mixture with an antibody specific to the antigenic substance to cause antigen-antibody reaction and measuring the amount of the precipitates formed, and a diagnostic kit for practicing the method are disclosed.

Abstract: Phthalazine derivatives represented by the formula ##STR1## and salts thereof which are useful for a luminescence immuno assay, or a process for preparing the same are disclosed.