152

be monitored via free programming as well as by control by the system maintenance personnel.

5187107

PATENT ABSTRACTS

B12 E N Z Y M E I M U N O A S S A Y A N D S A M P L E P R E T R E A T M E N T

- Michael I Watkins, Clifford R Bartlett, Edward T Liang, John M Pocekay, Mark A Staples as- signed to Bio-Rad Laboratories Inc

Denaturing agents used to pretreat test samples for immunoassays are neutralized and deac- tivated by the addition of a treatment agent which is a combination of a buffering agent in acid form and an agent for converting the sulfhydryl groups of the denaturing agents to a non-active form such as disulfides or alkylthio groups. The treatment agent serves this function without having sufficient denaturing activity by itself to interfere with subsequent steps of the as- say procedure. Also disclosed is a protocol for a vitamin B12 assay which involves a sequential rather than competitive binding of the BI2 with excess intrinsic factor followed by the binding of excess enzyme-labeled BI2 to any remaining in- trinsic and immobilizing such intrinsic factor on a solid phase. Various problems associated with BI2 assays are avoided by this technique.

5187260

P R O C E S S F O R T H E P R E P A R A T I O N O F A H I G H P U R I T Y P R O T A M I N E - D N A

C O M P L E X A N D P R O C E S S F O R U S E O F S A M E

Sharifa Karali, John K Barberii

A process is disclosed in which high purity protamine-DNA complexes are prepared by col- lecting nucleoprotamines specific developmental stages of a life form, specifically, amphibian, egg by low temperature processing. The process also includes the steps of sequential homogenization in a high concentration aqueous salt solution at a buffered low pH, followed by ultracentrifuga- tion to remove insoluble matter. Either a crude mixture or pure isolate of the complexes may be produced. Pure isolates require aqueous chloro- form extraction to isolate protein and to remove lipids. Lyophilization then removes chloroform and excess water. The isolate is then fractionated by single pass alumina chromatography. Dia- lysis against pure water removes salts. Repeated lyophilization removes excess water and con-

centrates single protamines and protamine-like proteins. The mixture may then be reconstituted with 5~ weight/volume heterologous or homo- logous DNA, in order to shield from charge toxi- city. Crude mixtures may be produced by precipitating the supernate of ultracentrifuga- tion in pure water, followed by ultracentrifuga- tion to sediment in solids. Lyophilization then removes any water from the damp solids. The crude solids are suitable for oral use, especially if utilized in gelatin capsules. Sterile filtration to in- jection quality aqueous form. Following isola- tion of the protamine-DNA complex, encapsulation of the prepared solid or aqueous protamine-DNA complexes in a specific carrier substance may be accomplished, depending upon the target tissue for the protamine. Several encapsulation carriers are known from prior art literature, such as, for example, liposomes and nanoparticles. The protamine-DNA complexes of the present invention are useful in inhibiting tumor growth, among other uses.

5188808

M E T H O D F O R M I X I N G L I Q U I D , S O L I D S A N D G A S A N D F O R

S I M U L T A N E O U S L Y S E P A R A T I N G G A S O R G A S A N D S O L I D S F R O M

T H E L I Q U I D

Launo L Lilja, Valto Makitalo, Stig-Eri Hul- tholm, Bror G Nyman, Pori, Finland assigned to Outokumpu Oy

The invention relates to a method for main- mining a continuous mixing extending through- out the transversal section of the reactor space in a liquid containing solids and gas, and for simul- taneously separating gas or gas and solids from the liquid. The invention also relates to an ap- paratus whereby the mixing is maintained, and simultaneously at least one phase is removed from the liquid under agitation. In a particularly advantageous fashion the method and apparatus of the present invention are suited for the stirring of bioreactors, as well as to removing gas and solids from the said reactors.

5188934

4 , 7 - D I C H L O R O F L U O R E S C E I N D Y E S A S M O L E C U L A R P R O B E S

Steven M Mencben, Linda G Lee, Charles Con- nell, N Davis Hershey, Vergin Chakerian, Sam Woo, Steven Fung assigned to Applied Bio- systems Inc