Serum replacement technique

Characterization of Latex Particles with Respect to Carboxyl Distribution. All latex samples were cleaned by the serum replacement technique (10). Diluted latex sample (3% by weight) was placed in the cell confined with a Nuclepore membrane and distilled deionized water was fed into the cell from a reservoir placed at 1.5 meters above the cell. The serum from the cell exit was collected and monitored with conductance measurement. 

One of the more commonly used techniques is that of serum rq)lacement [19]. The latex particles are confined in a stirred cell by a filtration membrane. Washing with water not only cleans the latex but the serum replacement technique can also be used to obtain the senuiL The cleaning process can be followed by monitoring, for example, the ctxiductivity of the serum. 

In the serum replacement technique (2, 3), the dispersion is confined in a stirred flow cell. The confinement of the... 

Charactaization of the water-soluble oligomers requires removal of the latex particles from the serum. This has been accomplished by ultrafiltration [163,164,166,174], serum replacement [167,168], or freeze-coagulation [173], followed by standard concentration techniques (e.g. evaporaton of water, or solvent extraction) or direct analysis of the aqueous solutions [163,164,166,174]. 

Fractionation techniques have made it possible to recover active o -antitrypsin from blood. Use of this product for intravenous replacement therapy in deficient individuals has shown that it is possible to increase levels in the serum to those of PISZ heterozygotes who experience no increase in pulmonary disease over the general population. Pulmonary lavage of patients transfused with this product showed that functional (Xj-antitrypsin reaches the alveolar structures. The Food and Drug Administration has approved weekly administration of purified serum-derived oq-antitrypsin to PIZZ and PI null individuals with pulmonary disease. Although serum levels of oq-antitrypsin increase to those believed to be protective, it has not been possible to show clinical improvement. Furthermore, viral transmission via blood products is a significant risk factor. 

Plasmapheresis This procedure is a further development of blood exchange (M.J. Lepore et at, 1967). The patient s plasma is separated by centrifugation or other appropriate techniques and discarded, so that the protein-bound and fat-soluble toxins circulating in the plasma are removed. This plasma volume is replaced by fresh plasma. At the same time, the separated corpuscular components of the patient s blood are reinfused. Serious complications may arise from the transmission of viral hepatitis and the occurrence of transfusion-related lung disorders (ARDS). Nevertheless, the method involved is simple and has been carried out successfully in individual cases (87, 91) even as plasma exchange with the administration of a high plasma volmne (1.3 1/hr over 8 hours). It has proved to be much more successful when the serum (ca. 31... 

Using this procedure, a skilled analyst can prepare five to six plates (480 to 580 samples) in an 8-hr workday. A similar type of procedure has been used for 96-well SPE for plasma, serum, Caco, rat-intestinal perfusate, liver micro-somes, and samples from several other matrices. Although more highly integrated plates, such as those consisting of 384 wells, could replace four of the 96-well plates, the extremely limited per-well sample volumes would make many common sample preparation techniques unfeasible. 

A recently developed variant of this method is the class-capture technique useful in the diagnosis of infectious diseases. This method is based on the observation that after the first infection primarily IgM antibodies (Section 5.1.1) are produced which are gradually replaced by IgG antibodies in chronic or recurrent infections. Vari jus laborious methods have been developed to separate IgG from IjM and to establish the relative proportion of antibodies in the two classes. In the very simple but powerful class-capture method, the presence of IgM can be detected by immobilizing an anti-IgM antibody which will capture the IgM from the serum. If the IgM contains antibodies, they will, in turn, be able to capture the antigen, which can be revealed by the methods shown in Figs. 2.2c or 2.2d. The titres of IgM and IgG antibodies can be established in parallel experiments. 

In addition to the recombinant vaccine presently in development, research on cocktails of monoclonal antibodies is being conducted at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, Maryland, to replace the despeciated horse serum. The cocktail approach will enhance the safety of the immunotherapy, and recombinant techniques will probably also reduce the cost of therapeutic antibody. 

Other cleaning techniques are repeated centrifugation with replacement of the serum, contacting the latex with an activated carbon cloth, and gel filtration (see ref. 18 and references therein). For the removal of residual monomer in lattices, steam stripping is sometimes used [24]. 

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