Plasma donors

The passivation of n-type dopants in Si was reported by Johnson et al. (1986) several years after it was well recognized that deep defects and shallow acceptors were passivated following exposure to an H2 plasma. Donor passivation effects had been missed by previous workers presumably because the in-diffusion of H into heavily n-doped Si is impeded when compared to undoped or p-type material. 

There are two protein replacement products available for A1AD, both pooled human plasma donor-derived products. Approval of these products was based upon replacement of serum AAT to the above-mentioned levels. Neither has been proven to prevent lung disease in a prospective, double-blinded placebo-controlled fashion, but retrospective registry data suggest a beneficial effect. However, protein replacement therapy has been very safe. Particularly remarkable has been the lack of an adaptive immune response by patients on therapy, which may relate to the genetic homogeneity of this A1AD population, in which approximately 95% have one particular missense mutant allele (PI Z). 

Cairns T, ChiuKS, Siegmund EG, et al 1986. Levels of plasticizer in the frequent plasma donor. 

Hepatitis A virns (HAV) Only a few reports on hepatitis A virus transmission have appeared (153,154). In 1992 an outbreak of icteric hepatitis A involving at least 83 patients with hemophilia A in Italy, Belginm, Ireland, and Germany was docnmented aU had been treated with a high purity factor VIII concentrate prodnced by one manufacturer (157,158) there was icterus in 93% and a diagnosis of hepatitis A was based on the presence of IgM anti-HA. The original sonrce of contamination was not definitively estabhshed, bnt it is possible that the virus did not originate from the plasma donors. 

The incidence of hepatitis C among donors varies considerably (from 0.2 to 3%) among US blood donors the prevalence was 0.36% in nnpaid volnntary donors, whereas it was 10% in commercial plasma donors (11). In another stndy, the per nnit risk of hepatitis C virns infection was 0.45% before testing had been introdnced, 0.19% after the introdnction of so-called snrrogate tests... 

While no confounding influences were detected regarding CML, plasma protein pentosidine was higher in AMD donors with hypertension or cardiovascular disease, as also found for CEP adducts. Plasma protein fructosyl-lysine provided an effective parameter to narrow the cause of increased AGEs, Except for 5 diabetic AMD donors, the AMD and control plasma donors in our study exhibited essentially the same fructosyl-lysine concentrations. When fructosyl-lysine, CML and pentosidine are all elevated, more information will be required for an accurate clinical assessment. In such cases, we suggest that CEP adduct levels may help rule out diabetic complications since plasma CEP adducts are elevated in AMD but not in diabetes... 

A method for the fractionation of plasma, allowing albumin, y-globulin, and fibrinogen to become available for clinical use, was developed during World War II (see also Fractionation, blood-plasma fractionation). A stainless steel blood cell separation bowl, developed in the early 1950s, was the earhest blood cell separator. A disposable polycarbonate version of the separation device, now known as the Haemonetics Latham bowl for its inventor, was first used to collect platelets from a blood donor in 1971. Another cell separation rotor was developed to faciUtate white cell collections. This donut-shaped rotor has evolved to the advanced separation chamber of the COBE Spectra apheresis machine. 

Blood can be collected ia the form of whole blood donations. In the United States, one unit, ie, 450 mL, of blood is collected from a healthy volunteer blood donor who is allowed to donate blood once every 10 weeks. A unit of blood is typically separated iato a red cell fraction, ie, red cell concentrate a platelet fraction, ie, random donor platelets (RDP) and plasma. 

Blood components are also collected through apheresis. In apheresis, advanced blood cell separators are used to collect one or more specific blood components from a donor. The cell separators collect blood iato a separation chamber, isolate the desired blood components, and return the blood components not needed to the donor. This procedure is performed on-line within one sterile disposable tubiag set. The two principal components collected through apheresis are plasma and siagle-donor platelets (SDP). 

Primary blood components iaclude plasma, red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes), and stem cells. Plasma consists of water dissolved proteias, ie, fibrinogen, albumins, and globulins coagulation factors and nutrients. The principal plasma-derived blood products are siagle-donor plasma (SDP), produced by sedimentation from whole blood donations fresh frozen plasma (FFP), collected both by apheresis and from whole blood collections cryoprecipitate, produced by cryoprecipitation of FFP albumin, collected through apheresis and coagulation factors, produced by fractionation from FFP and by apheresis (see Fractionation, blood-plasma fractionation). 

Full details of this work were pubHshed (6) and the processes, or variants of them, were introduced in a number of other countries. In the United States, the pharmaceutical industry continued to provide manufacturing sites, treating plasma fractionation as a normal commercial activity. In many other countries processing was undertaken by the Red Cross or blood transfusion services that emerged following Wodd War II. In these organisations plasma fractionation was part of a larger operation to provide whole blood, blood components, and speciaUst medical services on a national basis. These different approaches resulted in the development of two distinct sectors in the plasma fractionation industry ie, a commercial or for-profit sector based on paid donors and a noncommercial or not-for-profit sector based on unpaid donors. 

Plasma Collection. Human plasma is collected from donors either as a plasma donation, from which the red cells and other cellular components have been removed and returned to the donor by a process known as plasmapheresis, or in the form of a whole blood donation. These are referred to as source plasma and recovered plasma, respectively (Fig. 1). In both instances the donation is collected into a solution of anticoagulant (146) to prevent the donation from clotting and to maintain the stabiUty of the various constituents. Regulations in place to safeguard the donor specify both the frequency of donation and the volume that can be taken on each occasion (147). 

Estimates for a number of economic aspects of plasma fractionation can be made (200—206). The world capacity for plasma fractionation exceeded 20,000 t of plasma in 1990 and has increased by about 75% since 1980, with strong growth in the not-for-profit sector (Fig. 4). The quantity of plasma processed in 1993 was about 17,000 t/yr the commercial sector accounts for about 70% of this, with over 8000 t/yr in the form of source plasma from paid donors (Fig. 5). Plant capacities and throughput are usually quoted in terms of principal products, such as albumin and Factor VIII. These figures may not encompass manufacture of other products. 

Impurity-produced plasmas in semiconductors do not have to be compensated by charges of the opposite sign. These plasmas can be produced by introduction of either electron donors or electron scavengers, ie, hole producers, into semiconductor lattices. Thek densities range from a lower limit set by the abihty to produce pure crystals particles/cm ) to values in excess of 10 particles/cm. Plasmas in semiconductors generally are dilute, so that... 

MAO converts dopamine to DOPAC (3,4-dihydrox-yphenylacetic acid), which can be further metabolized by COMT to form homovanillic acid (HVA). HVA is the main product of dopamine metabolism and the principal dopamine metabolite in urine. Increased neuronal dopaminergic activity is associated with increases in plasma concentrations of DOPAC and HVA. COMT preferentially methylates dopamine at the 3 -hydroxyl position and utilizes S-adenosyl-L-methio-nine as a methyl group donor. COMT is expressed widely in the periphery and in glial cells. In PD, COMT has been targeted since it can convert l-DOPA to inactive 3-OMD (3-O-methyl-dopa). In the presence of an AADC inhibitor such as carbidopa, 3-OMD is the major metabolite of l-DOPA treatment. 

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. 

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