Pools, plasma

Inactivation and Removal of Viruses. In developing methods of plasma fractionation, the possibiHty of transmitting infection from human vimses present in the starting plasma pool has been recognized (4,5). Consequentiy, studies of product stabiHty encompass investigation of heat treatment of products in both solution (100) and dried (101) states to estabHsh vimcidal procedures that could be appHed to the final product. Salts of fatty acid anions, such as sodium caprylate [1984-06-17, and the acetyl derivative of the amino acid tryptophan, sodium acetyl-tryptophanate [87-32-17, are capable of stabilizing albumin solutions to 60°C for 10 hours (100) this procedure prevents the transmission of viral hepatitis (102,103). The degree of protein stabilization obtained (104) and the safety of the product in clinical practice have been confirmed (105,106). The procedure has also been shown to inactivate the human immunodeficiency vims (HIV) (107). 

In past years, treatment for patients with hemophilia A has consisted of administration of cryoprecipitates (enriched in factor VIII) prepared from individual donors or lyophilized factor VIII concentrates prepared from plasma pools of up to 5000 donors. It is now possible to prepare factor Vlll by recombinant DNA technology. Such preparations are free of contaminating viruses (eg, hepatitis A, B, G, or HlV-1) found in human plasma but are at present expensive their use may increase if cost of production decreases. 

In the blood, 2.5-3.0 g of hemoglobin iron circulates as a component of the erythrocytes (top right). Over the course of several months, the flexibility of the red blood cells constantly declines due to damage to the membrane and cytoskeleton. Old erythrocytes of this type are taken up by macrophages in the spleen and other organs and broken down. The organic part of the heme is oxidized into bilirubin (see p. 194), while the iron returns to the plasma pool. The quantity of heme iron recycled per day is much larger than the amount resorbed by the intestines. 

Figure 9.17. Overview of the manufacture of Ceprotin. As the active ingredient is derived directly from pooled human plasma, particular emphasis is placed upon ensuring that the finished product is pathogen-free. Precautions entail the incorporation of two independent viral inactivation steps and high-resolution chromatographic purification. Additionally, extensive screening of plasma pool source material for blood-borne pathogens is undertaken. Viral screening is undertaken using a combination of immunoassay and PCR analysis for the presence of viral nucleic acid...

The interassay variation was assessed in a plasma pool, which was stored at -20°C and analyzed 26 times over an 8-month period. The coefficients of variation (CVs) ranged from 6.1 to 8.9% with the following exceptions glutamine decreases steadily from 587 to 447 pmol/1 with a concomitant increase of glutamic acid from 62 to 164 pmol/1. Cystine decreased from 35 pmol/1 to undetectable. Tryptophan, arginine, methionine, asparagine, and proline had CVs slightly in excess of 10%. 

Figure 19.1 Physiological pharmacokinetic model for evaluating in vivo disposition of a macromolecular drug. (A) A multi-compartment model in which every tissue compartment is connected with the plasma pool by blood flow. (B) Tissue uptake of a drug from vascular space to tissue parenchyma.

Hop, C. E. Wang, Z. Chen, Q. Kwei, G. 1998. Plasma-pooling methods to increase throughput for in vivo pharmacokinetic screening. J. Pharm. Sci., 87, 901-903. 

In normal tissues of the vasculature, TFPI is produced by megakaryocytes and the endothelium (102). Once produced, this TFPI is stored in three intravascular pools. These pools are located in the plasma, in platelets, and bound to the endothelium (103). The smallest pool of TFPI is found in the platelets, accounting for less than 2.5% of the intravascular total. This small pool of TFPI is released upon platelet activation (104). 10% to 50% of the intravascular TFPI is in the plasma. Most plasma-based TFPI is bound to plasma lipoproteins (104,105). Approximately 5% of the plasma pool of TFPI circulates in the free form (103,104,105). The lipoprotein-bound TFPI is reported to be of relatively low inhibitory activity (104). The largest pool of TFPI is found bound to the endothelial surface (103,104,106). This pool can account for 50% to 90% of the total intravascular TFPI,... 

The presence of the different suPAR variants in EDTA plasma from a prostate cancer patient was analyzed by size exclusion chromatography and measurement of the fractions obtained with the three different TR-FIAs. This EDTA plasma contained detectable amounts of uPAR(I) in contrast to an EDTA plasma pool from healthy donors. The levels of suPAR measured with TR-FIA 2 were considerably higher and eluted at a later position in the patient sample than in the donor plasma, thus indicating the presence of suPAR(II nf) in the patient sample [108], In a recent study, the concentrations of uPAR(I) as well as the calculated suPAR(II-III) were found to be significantly elevated in serum samples from patients with prostate cancer compared to the concentrations in serum from men with benign prostatic conditions. Specific measurements of uPAR(I) were found to improve specificity of prostate cancer detection [142],... 

I) Consider three structurally similar Cis steroids —testosterone, an-drostenedione, and dehydroepiandrosterone. Each of these compounds is secreted into the blood stream by glands, and after provoking its biochemical effect, is metabolized and excreted. If the only source of the plasma pool were provided by the glandular secretion of the hormone, then the secretion rate would be used to calculate the plasma concentration. However, the picture in the case of the three Ci steroids is complicated by the fact that the three compounds are peripherally interconvertible. Since both glandular secretion and peripheral conversion of precursors contribute to the plasma pool, the production rate is used to... 

Table V shows that the amount of adsorption onto Silastic from plasma is significantly depressed below its saturation value measured in buflFer presumably because of competition from other components of the plasma. The diflFerence in adsorption from the two plasma pools may result from the increased fibrinogen concentration in one pool which would allow more eflFective competition for adsorption onto Silastic and result in enhanced adsorption. Since the adsorption of fibrinogen onto poly (HEMA)/Silastic from plasma is not so greatly depressed relative to adsorption from buflFer (see Table V), an increase in plasma fibrinogen concentration might not have so large an eflFect on adsorption onto poly-(HEMA)/Silastic as it apparently does on adsorption onto Silastic itself.

Plasma zinc is known to decrease following use of oral contraceptive agents (73,74). Our recent data indicate that whereas the plasma zinc may decline, the zinc content of the red blood cells increases as a result of oral contraceptive agents administration. This phenomenon may merely mean a redistribution of zinc from the plasma pool to the red cells. Alternatively, oral contraceptive agents may enhance carbonic anhydrase (a zinc metalloenzyme) synthesis, thus increasing the red cell zinc content. 

The immunoglobulins are obtained from the plasma pools by fractionation methods that are based on ethanol precipitation in the cold with rigorous control of protein concentration, pH and ionic strength (Cohn et al., 1946). The variation of... 

Calcium can be redistributed among the three plasma pools, acutely or chronically, by alterations in the concentration of protein and small anions, changes in pH, or changes in the quantities of free calcium and total calcium in the serum (Figure 49-2). 

Milhaud et al. (MIO) studied the turnover of calcium in the plasma pool both in control and in thyrocalcitonin-treated animals. In fasted controls, the release of unlabeled calcium into the pool as a result of bone catabolism caused a fall in plasma calcium specific activity following thyrocalcitonin treatment, however, the specific activity remained unaltered despite the hypocalcemia, implying a suppression of bone resorption. They claimed good agreement between the experimental find-... 

Several different plasma-derived factor VEI products are avaUable (see Table 100 ). These products are derived from the plasma of thousands of donors, and therefore potentially can transmit infection. Donor screening, testing plasma pools for evidence of infection, viral reduction through purification steps, and viral inactivation procedures (e.g., dry heat, pasteurization, and solvent detergent treatment) have all resulted in a safer product. No cases of HIV transmission from factor concentrates have been reported since 1986. However, there have been isolated reports of hepatitis C infection with the use of plasma-derived products. Additionally, there have been outbreaks of hepatitis A viral infections associated with plasma-derived products, likely because solvent detergent treatment does not inactivate this nonenveloped virus. Parvovirus has also been reported to be present in both plasma-derived and recombinant factor VIII products. " Finally, there remains concern about the possibility for infection with as yet unidentified viruses that currently used methods would not inactivate. 

Results from a substrate assay may be reported in several different ways. For example, six different ways to report the level of the thrombin inhibitor, antithrombin III, have been used (S25). One system fiimiliar to biochemists would be nanokatals (nkat) per unit of volume. A nkat is defined as the amount of enzyme which converts one nanomole of substrate per second. The second system, which would be more fiimiliar to the coagulationist, reports results in terms of percent of normal or plasma equivalent units (PEU), one PEU being the amount of a substance present in 1 ml of a standard laboratory plasma pool drawn from normal donors. This question on reporting units becomes more important when the substrate assays are substituted in the global assays, PT and PTT. The latter clot-endpoint tests measure the total effect of many fiictors and it is known that the PT and PTT are insensitive to changes in some of the fectors over a wide range, i.e., 60-120%. This point will be discussed later in Sections 6 and 7. 

Human Plasma pooled human plasma, mixed sex, sodium citrate anticoagulant (Innovative Research, Novi, Ml, USA) (tee Note 1). Store aliquots at -20 °C. Store thawed aliquot on ice and flash-fireeze the remaining blood sample at end of assay day. 

The arrow with an asterisk indicates the site of entry of the oral Se tracer. Arrows between compartments represent pathways of fractional transport. Compartments depicted as rectangles represent delays. Compartments G1, G2, G3, 3 gut compartments, probably the small intestine ENT, enterocytes (intestinal cells) HPL, compartment in hepato-pancreatic subsystem or lymphatic system L/P, liver and pancreas LI, large intestine T1, T2, peripheral tissues, e.g., skeletal muscle, bone, kidney. Feces and urine compartments are drawn in the shape of test tubes to represent fractional (single) collections. The model includes absorption distributed along the gastrointestinal tract, enterohepatic recirculation, four kinetically distinct plasma pools, P1-P4, a subsystem consisting of liver and pancreas, and a slowly turning-over tissue pool. 

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