Abstract: A method for forming vesicles is described, wherein a lipid coating is formed onto a deformable surface. During hydration, the lipid coating is fragmented by deformation of the surface. The resulting fragments of the lipid coating are dispersed in the hydrating medium, so as to be subjected to multidirectional hydration, whereby formation of vesicles is accelerated. In the preferred embodiment, such surface is defined by a plurality of water-swellable particles formed of a polymeric material.

Abstract: A transport system is provided in which a plurality of samples are introduced into a carrier stream flowing through a conduit, whose inner surface is coated with an immiscible liquid film. The carrier stream can be a sequence of alternating gas and liquid segments which are in direct contact with each other and, thus, not encompassed by the immiscible liquid. Samples are introduced at various points along the conduit and, thus, the system allows for the collection and transport of samples from a plurality of remote locations to at least one central receiving station where they can, for example, be analyzed. Carryover between successive samples to be transported is effectively eliminated.

Abstract: Continuous flow metering apparatus and methods using liquid position sensors in conjunction with flow-stopping valves control (meter) fluid, e.g. sample/reagent/air, aspiration into a single conduit, such as in a continuous flow system. Air or other gas separates selected ones of the liquid segments. The volume of the aspirated segment is established by sensing a flow parameter of the segmented stream of a selected one of the sensors. A pulse is generated by the sensors (detectors), for example due to the change of light intensity at a liquidair interface traversing the conduit. The signal pulse from a sensor causes the actuation of a selected one of the valves and stops aspiration (flow) of the liquid by traversing the flow path in the conduit through an air segment. The valve cuts through air only. Therefore, the body of the valve does not contact reagent or sample liquid by this action and the risk of carryover contamination is avoided. With the aspiration cycle completed, the input end of the conduit, e.

Abstract: The integral reagent dispenser disclosed comprises a reagent dispenser component provided with a reagent dispenser well having an opening adapted to present a liquid reagent for withdrawal therethrough and means to position a lens of liquid immiscible with said reagent between the reagent and the opening of said well. For example, the dispenser can have suitable dimensions and an inner surface which combine with the wetting characteristics of the reagent to form a concave reagent meniscus suitable to reliably position a lens of immiscible liquid thereon. The lens so formed is centrally located by the concave shape of the meniscus. Preferably, the reagent dispenser further includes an integrally associated source of reagent.

Abstract: The present invention relates to apparatus and method for separating, by centrifugation, blood lymphocytes from other leukocytes in a blood sample. Small dense particles, either wetted or suspended in a physiological, hydrophilic medium, and a chemically inert hydrophobic barrier material are initially located in a suitable container. When the blood sample is added to the container, the particles are phagocytized by the monocytes and granulocytes, so as to increase their specific gravities. Upon centrifugation, the barrier material, whose specific gravity is only slightly greater than the specific gravity of the lymphocytes and less than the respective specific gravities of the phagocytic cells which have ingested particles and of the erythrocytes (red blood cells) in the blood sample, forms a rigid barrier therebetween, allowing harvesting of the lymphocytes, substantially free of contamination.

Abstract: Vitamin B.sub.12 in liquid samples, such as human serum or human plasma, is assayed by a competitive binding technique using intrinsic factor and certain labelled vitamin B.sub.12 derivatives. The labelled derivatives are formed from the (d)-monocarboxylic acid isomer of vitamin B.sub.12, which isomer is free from other monocarboxylic acid isomers (and derivatives thereof) of vitamin B.sub.12, by binding to the (d)-isomer, via the carboxylic group, a compound which is itself a label (e.g. an enzyme) or which comprises a label (e.g. a fluorophore), or to which a label is attached (e.g. a histidine ester to which .sup.125 I is attached). The labelled derivatives of the (d)-monocarboxylic acid of vitamin B.sub.12, free from other isomeric monocarboxylic acids and derivatives, are novel and constitute one aspect of the invention.

Abstract: In the immunoassay of a particular protein in a biological fluid, there is frequently interference in the assay by other proteins present in the fluid, e.g. by complement factors or antibodies in human serum. The interference so caused can be avoided by subjecting the fluid to protein-digestion, using for example an enzyme such as pepsin, as a result of which the particular protein of interest, or a fragment thereof, can be assayed without interference by the other proteins. Also, radioallergosorbent tests for particular IgE antibodies can be improved in sensitivity and accuracy, by subjecting the absorbed IgE to enzymic digestion, and then assaying a fragment thereof.

Abstract: New and improved method and apparatus for the correction of coincident errors attendant the automated detection and counting of mixed particles having detectable characteristics of different levels in particle counting applications wherein the detection of "dominant" particles under coincident particle conditions, renders undetectable the "dominated" particles, with resulting inaccuracy in the "dominated" particle count. Such inaccuracy is corrected by modifying the "dominated" particle count in accordance with the time duration of the signals which are generated attendant the detection of the "dominated" particles.

Abstract: A test-tube assembly and method for carrying out immunoassays. The apparatus features two independent components, the first having a series of test-tubes fixed to a support and equidistantly dependent therefrom, and the second having a base including magnets permanently fixed therein, the two components being releasably couplable to hold the lower ends of the test-tubes adjacent the magnets in the base.

Abstract: A particle counting assay for haptens (small non-protein monovalent substances having a molecular weight below 1500) comprises mixing a liquid sample (e.g. of human origin) containing the hapten, with finely divided inert particles bearing the same hapten (or a specific analogue thereof), an agglutinator such as RF or C1q, and a measured amount of antibody, which amount is insufficient to cause agglutination of all the particles. The amount of hapten is determinable by measuring the extent of the agglutination.

Abstract: New and improved apparatus and method for thorough, non-invasive mixing of a flowing fluid stream, either continuous or segmented, are provided and, as disclosed, are embodied in a mixing conduit which comprises a plurality of interconnected bends, which may be in the form of arcuate coils or sections, successive arcuate sections being operable to establish secondary flow patterns in differing orientations within the flowing fluid stream, or individual segments thereof. Such arcuate sections may be disposed in a same plane, if formed in serpentine fashion, or in non-parallel, preferably orthogonal planes, if formed in a tortuous fashion. Also, the arcuate sections, or a series thereof may be formed in stacked fashion and located in essentially parallel planes.

Abstract: Transferring a solute from a first to a second liquid solvent, utilizing a membrane selectively permeable by a gas and impermeable by the liquids, which method includes the steps of: flowing the first liquid along said membrane, evaporating the first liquid across the membrane to dryness, said evaporation leaving a residue of the former solute on the membrane, and flowing the second liquid along the membrane for dissolving the residue.

Abstract: In the immunoassay of antigens in liquids, a reaction mixture is formed containing the liquid under assay, labelled antigen, and a mixed binding reagent which contains an antigen-binding site and a label-binding site, the two sites being spaced apart in the reagent so that a single molecule of labelled antigen cannot bind to both sites. The label is one whose activity is changed upon binding to a label-binding site, and the amount of antigen in the original liquid sample is determined by measuring the activity of the label in the reaction mixture. A preferred label is a fluorophore. The mixed binding reagent preferably consists of two antibodies linked together.

Abstract: Immunoassays for antigens or haptens are effected using, instead of an immunoglobulin antibody, the F(ab').sub.2 fragments thereof. In this way, interference from endogenous RF and Clq in the fluid under assay is avoided without the necessity of pre-treating the fluid to remove or inactivate the RF or Clq. The assays may be of various types including latex agglutination and competitive binding assays. A reagent for such use comprising F(ab').sub.2 fragments insolubilized on a water-insoluble substrate, especially a particulate substrate, is described.

Abstract: In particle agglutination immunoassays for an analyte (e.g. an antigen or antibody) in a liquid sample (e.g. human serum), interferences arise due to non-specific protein-protein interactions and the like. These interferences are reduced or overcome by including in the assay mixture a chaotropic or chaotropic-like agent, in a carefully controlled amount. Such agents include guanidine, guanidinium hydrochloride or thiocyanate, sodium or ammonium thiocyanate, and urea, sodium chloride and ethylenediamine tetraacetic acid.

Abstract: The amount of vitamin B.sub.12 in solution in a liquid is determined by mixing a sample of the solution with vitamin B.sub.12 -binding proteins from chicken serum in a pH of about 12.8 to 13.2, and then analyzing a component of the mixture. In preferred procedures, especially useful in assaying human sera, a competitive binding technique is employed utilizing labelled vitamin B.sub.12 and a buffer containing cyanide ion. By operating at very high pH and with chicken serum proteins, the assay can be conducted relatively simply and with very accurate results.

Abstract: Methods and apparatuses are featured for preconcentrating immunological reactants prior to their contact and reaction to enhance the rate of reaction for separating reacted and unreacted reactants and, also, to increase the sensitivity at the detector-measuring system. The preconcentration of the reactants finds particular use in immunoassays, where very often an immunospecies is very dilute causing a time consuming and/or insensitive assay. The preconcentration and separation are accomplished within the reaction medium resulting in a simplified and compact apparatus.

Abstract: A liquid, particularly but not exclusively a liquid of human origin such as blood serum or urine, is immunoassayed for antibodies, antigens or antibody: antigen complexes, using as a reagent in the analysis an active fraction from mouse ascitic fluid. This active fraction is a euglobulin and has the ability, like human C1q, to combine with antibody:antigen complexes but not with free antibody or antigen. Unlike human C1q, however, it remains active at high pH's and its activity is not destroyed by 0.1 M putrescine or 0.1 M hydrazine, so analyses on human body fluids can be carried out at high pH's or in the presence of putrescine and hydrazine, without interference from endogenous human C1q. The active fraction is a very broadly applicable reagent in immunoassays and particularly useful in techniques involving agglutination of latex particles.

Abstract: Method is provided for the operation of substantially constant flow rate sample analysis apparatus in such manner that the adverse effects upon sample analysis accuracy of periodic variations in analysis apparatus flow rate and/or sample-analysis reagent proportioning are negated to insure the sample-to-sample consistency and accuracy of the sample analysis results.