Commercial Human Serum Research Articles

Evidence for a concentration-dependent polymerization of a commercial human serum albumin

Polymerization of a commercial human serum albumin (Sigma A-1887) was investigated by two different techniques, high-performance liquid chromatography and gel electrophoresis. The chromatographic technique was based on the frontal analysis principle using a column which excludes polymers but retains monomers. The results allowed the determination of the monomer-polymer affinity constant, X = 526 ± 100. The electrophoresis technique was performed with a polyacrylamide gel containing sodium dodecyl sulphate in order to separate the different polymer species according to their molecular weights. The two techniques gave results in good accordance and showed a concentration-dependent aggregation. The higher the human serum albumin concentration, the more the monomer proportion decreases.

The influence of citrate ions on the radiochemical purity of 99Tc m-Human Serum Albumin

During the development of a 99Tc m -Human Serum Albumin kit variations in the radiochemical purity of the product were observed when albumin preparations from different sources were used. Analysis by gel filtration on Biogel P-4 showed that some commercial human serum albumin preparations contained an unidentified compound which was very easily labelled with 99Tc m . The presence of some citrate in albumin preparations was possible and the investigations described were undertaken in order to confirm this possibility.

Antibody to group B Streptococcus type III in human sera measured by a mouse protection test.

Antibody to group B Streptococcus type III (GBS-III) was measured in human plasma and sera by using a test which measures the ability to protect outbred albino mice from an intraperitoneal challenge of GBS-III calculated to be lethal to 90% of the mice (LD90 dose). Of three samples from three different lots of commercial human immune serum globulin, none were protective despite the presence of antibody to the native type III polysaccharide. Nine specimens were tested from recipients of multivalent pneumococcal vaccine, and none were protective. Five specimens were tested from recipients of GBS-III polysaccharide vaccines who had responded with greater than 50 micrograms of specific antibody per ml in the blood. All of these were protective and could be diluted to titers of 1:10 to 1:40. Of two prevaccination sera with low levels of specific antibody, neither was protective. An unexpected finding which may limit the sensitivity of the mouse protection assay was that the human immune serum globulin and human serum with a very low level of antibody appeared to increase the lethality of the GBS-III test strain, resulting in LD50 values reduced to 0.01 of the usual LD50.

Effect of Multiple Sclerosis Serum on Ventral Root Responses in Isolated Frog Spinal Cord

Serum from patients with multiple sclerosis (MS) and other diseases was added to the medium perfusing isolated hemisected frog spinal cord, and the effect on ventral root responses (VRR) tested. As control, a standardized commercial human serum (Moni-trol I) was used. In 25 out of 40 spinal cord preparations Moni-trol gave inhibition of VRR ranging from 2.8 to 23.1%. 76% of the tests with confirmed MS sera showed inhibition of VRR, after deduction of the control serum effect, while 53% of the tests with sera from other diseases were inhibitory. Sera from cases of suspected but clinically unconfirmed MS gave strong inhibition (above 20%).

A New Specific Quantitation‐in‐Gel Method Differentiating Commercial Human Serum Standards Intended for RID Analyses

A rapid, sensitive technique is described which measures small amounts of protein applied on agarose gel containing specific antibody. Alternating current through the gel reduces the influence of diffusion, and specific immunoprecipitate spots are formed. Their density after staining is proportional to applied protein. Quantitation of IgG and IgA in human serum standards was highly reproducible (P less than 0.001, Spearman coefficient of rank correlation test), and as little as about 35 ng Ig could be detected. Results are available within hours. Human sera and some purified preparations of 7S IgG and secretory IgA were grouped according to immuno-gel filtration findings. The group of samples containing fragments, aggregates, or unusually small amounts of monomeric IgG or IgA was also differentiated by specific immunoprecipitate spot (SIS) analysis from those mainly monomeric in character (Wilcoxon rank test, P less than 0.02). A World Health Organization reference serum (67/97) was used as standard. The study indicates that a human serum pool stored in aliquots at -20 degrees C is a good standard for quantitating serum IgG and IgA and that purified preparations are no better. It is suggested that the SIS assay could be advantageously applied to screening biologic fluids for unusual amounts or types of IgG and IgA.

Rapid detection of contaminated intravenous fluids using the Limulus in vitro endotoxin assay.

Intravenous fluids and administration sets may become contaminated with gram-negative bacteria during use and result in a life-threatening situation to the patient. The Limulus in vitro assay for endotoxin was used in two patients whose parenteral fluids had become contaminated with Pseudomonas aeruginosa. This test allowed rapid detection of the contaminated intravenous fluids and demonstrated a concomitant endotoxemia in both patients. The same strains of pseudomon were subsequently cultured from each patient's blood, intravenous catheter tip, and parenteral fluid and administration set. A different serotype of pseudomonas was unique to each patient, indicating two separate and unrelated cases of accidental contamination of the administration sets. Endotoxin-like activity was also demonstrated from several brands of commercial human serum albumin, which may contribute low-level activity detectable by the Limulus assay.

Phospholipase activity associated with serum albumin

A phospholipase A 2 has been found in association with several commercial human and bovine serum albumin preparations. Activity is maximal between pH 6.0 and 8.0 and has been demonstrated using as substrates [1- 14C]oleate-labeled Escherichia coli after autoclaving the labeled bacteria, and purified [1- 14C]fatty acid-labeled phosphatidylethanolamine. The rates of breakdown of the major E. coli phospholipids were roughly comparable. The phospholipase activity seems distinct from triglyceride-splitting activities in association with albumin, described by others. The presence of phospholipase A in serum albumin preparations, often used in experiments with cells and tissues in vitro, may influence the results.

Rapid Detection of Contaminated Intravenous Fluids Using the Limulus In Vitro Endotoxin Assay

Intravenous fluids and administration sets may become contaminated with gram-negative bacteria during use and result in a life-threatening situation to the patient. The Limulus in vitro assay for endotoxin was used in two patients whose parenteral fluids had become contaminated with Pseudomonas aeruginosa. This test allowed rapid detection of the contaminated intravenous fluids and demonstrated a concomitant endotoxemia in both patients. The same strains of pseudomon were subsequently cultured from each patient's blood, intravenous catheter tip, and parenteral fluid and administration set. A different serotype of pseudomonas was unique to each patient, indicating two separate and unrelated cases of accidental contamination of the administration sets. Endotoxin-like activity was also demonstrated from several brands of commercial human serum albumin, which may contribute low-level activity detectable by the Limulus assay.