IGF-I was released from binding proteins by acid-ethanol extraction, followed by neutralization and cryoprecipitation
Fresh frozen plasma, cryoprecipitation
and prothrombin complex were given to correct coagulopathy.
Cryoglobulinemia was assessed using tube and gel-diffusion cryoprecipitation
(18) (OKAZAKI et al., 1998).
Sample processing - To prevent cryoprecipitation
of VWF and other proteins, blood samples for VWF assays should be transported to the laboratory at room temperature.
Before assay, IGF-I was extracted with acid-ethanol cryoprecipitation
(Breier et al., 1991).
(2) The processed serum is observed for cryoprecipitation
by daily inspection at 4[degrees]C for seven days.
Cryoglobulin was investigated using both tube and gel cryoprecipitation
. (6) Smooth muscle IgG antibodies were tested by indirect fluorescent antibody test using antigenic substrates of rodent rat liver-kidney-stomach sections and sera diluted at 1:40.
The IGF-I in plasma was extracted with acid-ethanol cryoprecipitation
and analyzed using specific radioimmunoassay kits consisting of anti-hIGF-I, [sup.125]I-IGF-I and hIGF-I (Diagnostic System Laboratories, USA).
It is essential that fasting serum samples be collected at 37[degrees]C to avoid false positives due to cryoprecipitation
of lipoproteins or false negatives due to premature cryoprecipitation
of immunoglobulins, rheumatoid factor, and complement (3).
Others are made of a variety of materials designed to selectively retain specific plasma components by cryoprecipitation
(removal of cryoglobulins) or affinity adsorption (such as removal of IgG-class antibodies by adsorption to Staphylococcus protein A).
These cases remind us that IgM monoclonal proteins (M-proteins) have earned a reputation as saboteurs of many laboratory assays owing to their self-aggregation, aggregation of latex particles, binding to analytes and reagents, and cryoprecipitation
. One additional point is that some IgM M-proteins also play havoc with their own detection and measurement by electrophoretic techniques.
Cryoglobulins that precipitate significantly at 20 to 30 C and as high as 36 C have been described(2) and may be associated with more serious symptomatology than other cryoglobulins with a lower cryoprecipitation
point, present in significantly higher concentrations.(1)