Instrumentation, Assay and Equipment Design

4830510 substantially fluid-tight seal. The gel casting deck has sidewalls which are slanted toward one

O P T I C A L A S S A Y M E T H O D F O R another so that when the gel is submerged in bur- S T O R E D H U M A N P L A T E L E T S fer solution during electrophoresis, the gel's ten-

dency to float is stIbstantially impeded. The Brian J Bcllhouse, Islip, Oxfordshire, United combs which form wells in the gel are referenced Kingdom to the side of the gel casting deck itself so as to

ensure uniformity and accuracy of well depth. The viability of a pack of stored blood platelets Safety features prevent the eleetrophoresis tank is monitored by gripping the pack between two from functioning if removed from its protective plates (6) and (7) which are closed to pinch housing. together the walls of the bag (10) along an L- shaped seal (14), leaving a channel (17), 4830726 squeezing a part (15) of the bag by means of a reciprocating plunger (19), so that the platelets S E P A R A T I O N O F L A R G E D N A continually flow to and fro between the part (I 5) M O L E C U L E S IN A L T E R N A T I N G and the part (16), through the channel (17), and A S Y M M E T R I C E L E C T R I C F I E L D S passing a beam of light from an LED (27) through the channel (17), to a photoresistor (29). Thomas D Stamato, Nicholas Dcnko assigned The AC signal from the photoresistor cor- responds to the fluctuations in the intensity of to The Wistar Institute the light passing through the channel (17) and the amplitude of this signal is representative of A method of separating DNA molecules by gel the viability, and hence the clinical acceptability, electrophoresis is disclosed which employs alter- of the platelets, nate application of high and low strength electric

fields in opposite directions to a gel matrix con- taiqing DNA. The high strength field is main- tained for a shorter interval than the low

4830725 strength field, and the ratio of the product of the low strength field and its pulse interval to the

E L E C T R O P H O R E S I S A P P A R A T U S product of the high strength field and its puIse interval is greater than 4:1 and sufficient to pro-

Mar lkrninger, Michael Schuette assigned to duce a net migration of the DNA molecules in Life Technologies Inc the direction of the low strength field.

An apparatus for casting an agarose gel and for conducting an electrophoresis process is dis- 4830959 closed. An electrophoresis tank supporis a gel casting deck having open ends which are scaled E L E C T R O C H E M I C A L E N Z Y M I C by wedge dams to form a cavity for containing A S S A Y P R O C E D U R E S the molten agarose as it gels. The wedge dams are pulled downward by gravity into wedge-shaped Calum J McNeil, Joseph Bannister, Glasgow, slots. The weight of the wedge dams in the wedge United Kingdom assigned to Medisens¢ Inc slots presses the wedge dams against the open ends of the gel casting deck so as to provide a Electrochemical detection of mediator level is

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