Effect of delayed blood processing on the yield of factor VIII in cryoprecipitate and factor VIII concentrate

Current standards for the preparation of factor VIII (FVIII) concentrates from human plasma recommend separation of plasma from red cells (RBCs) within 6 hours of blood donation, thereby reducing the volume of plasma from donated whole blood available for processing to FVIII concentrate. The decay of FVIII clotting activity (FVIII:C) in whole blood and plasma stored at 22 and 4 degrees C and the recovery of FVIII:C in cryoprecipitate and FVIII concentrate prepared from plasma separated from whole blood stored overnight at 4 degrees C were investigated. In whole blood stored at 22 degrees C and plasma stored at either 4 or 22 degrees C, 90 percent of the original FVIII:C was present at 6 hours, 80 percent at 12 hours, and 65 to 70 percent at 18 hours. At these times lower levels of FVIII:C were recovered from whole blood stored at 4 degrees C, that is, 84, 68, and 56 percent, respectively. In cryoprecipitates prepared from plasma separated from RBCs after 18 hours' storage at 4 degrees C (18-hour plasma), 43 percent of FVIII:C activity was recovered, as compared with 61 percent recovered from standard plasma separated within 6 hours of donation (6-hour plasma), p less than 0.05. With large-scale preparation of FVIII concentrates, however, the yield of FVIII:C was similar whether 18- or 6-hour plasma was used. Thus FVIII concentrates--but not cryoprecipitates--can be prepared from plasma separated from whole blood stored at 4 degrees C for up to 18 hours without undue loss of potency.     

Crotalocytin: recognition and purification of a timber rattlesnake platelet aggregating protein

After being envenomated by the timber rattlesnake, a patient was found to have a platelet count of 5000 per microliter, prothrombin time and activated partial thromboplastin time both greater than 150 sec, plasma fibrinogen 0 mg/dl, and fibrinogen split products 2560 microgram/ml. However, this patient did not appear to have acute disseminated intravascular coagulation since coagulation factors II-XII were normal. We postulated that this venom contained, in addition to a fibrinogen clotting enzyme, a platelet activating protein, Crotalocytin. Crotalocytin was purified from crude timber rattlesnake venom by Sephadex G-100 gel-filtration, low ionic strength precipitation, and DEAE-A50 Sephadex chromatography. By sodium dodecyl sulfate gel electrophoresis and gel-filtration Crotalocytin was a single chain polypeptide, molecular weight 55,000. Thrombocytopenia after timber rattlesnake bite appeared to be due to a protein that directly activated platelets. Timber rattlesnake bite mimicked the clinical presentation of disseminated intravascular coagulation.     

Teaching the future teachers in geriatrics: The 10-year success story of the European Academy for Medicine of Aging

While celebrating the 10th anniversary of the European Academy for Medicine of Aging (EAMA), former students and EAMA members identify 10 major factors that led to the success of the EAMA: (i) extremely motivated academic geriatricians anticipating the future care needs of the oldest old Europeans; (ii) EAMA's exclusive goal 'to teach the future teachers in geriatrics'; (iii) an excellent location in Switzerland with outstanding teaching facilities; (iv) a residential course of four 1-week sessions over 2 years consisting of innovative and contemporary content with the strong involvement of the EAMA's scientific board members; (v) a multicultural melting pot of young, promising geriatricians (from 24 different countries) who constitute the academic geriatric relief of tomorrow; (vi) numerous teachers and experts from all over the world; (vii) permanent and informal interaction between students and teachers; (viii) students' evaluations show marked progress in regard to scientific content, formulation of take-home messages and techniques of oral presentation before and after each course (over 90% of the participants of the first four courses were promoted and 20% obtained a full professorship in geriatrics); (ix) the well-designed EAMA concept is confirmed and validated with the recent accreditation by the European Community and the European Union Geriatric Medicine Society; and former students constituting a strong international network have been able to launch similar courses in elsewhere (Middle East Academy for Medicine of Aging; Latin America Academy for Medicine of Aging; Saint Louis University Geriatric Academy; and the European Nursing Academy for the care of the olders).     

The ontogeny of key endoplasmic reticulum proteins in human embryonic and fetal red blood cells

Recently, using immunohistochemical methods, we surprisingly found that endoplasmic reticulum glucose-6-phosphatase is present in human embryonic and fetal red blood cells (RBCs) but not in adult RBCs. The fact that an endoplasmic reticulum enzyme, whose major site of expression in adults is the liver, is present in human embryonic and fetal RBCs, particularly nucleated cells, indicated that it would be sensible to determine whether these cells also contain other endoplasmic reticulum enzyme systems normally found in adult liver. Therefore, we have studied the expression of other endoplasmic reticulum proteins and found that human embryonic and fetal RBC precursors contain other protein components of the glucose-6- phosphatase system, ie, the phosphate and glucose transport proteins as well as other enzymes (eg, uridine diphosphate- glucuronosyltransferases, cytochrome P450 isozymes, nicotinamide adenine dinucleotide phosphate cytochrome P450 oxidoreductase, and prostaglandin H synthase). In addition, we also found the predominantly cytosolic markers 15-hydroxyprostaglandin dehydrogenase, prostaglandins PGE2 and 13,14-dihydro-15-keto-PGE2. The expression of key enzymes that control glucose production, detoxification of endobiotics and xenobiotics, and the regulation of prostaglandin levels in embryonic and early fetal RBCs means that these cells may have an important role in protecting the developing conceptus before it establishes an efficient circulation and before all tissues fully express their normal complement of these enzymes.     

Heterogeneity of the human CD4+ T-cell population: two distinct CD4+ T- cell subsets characterized by coexpression of CD45RA and CD45RO isoforms

Activation of unprimed CD4+CD45RA+/RO- T cells results in a gradual loss of CD45RA expression concomitant with the acquisition of CD45RO. It has been suggested that this conversion occurs in vivo through a CD45RAbright/RObright stage. Next to this small CD45RAbright/RObright subset (Dbright), a larger subpopulation that expresses both RA and RO isoforms at low levels (Ddull) can be found in the circulating CD4+ T- cell population of all donors. The properties of the latter population are largely undefined. Here, we show that Ddull cells have an intermediate phenotype for antigens such as CD31, CD621, CD58, and CD95 that are differentially expressed on unprimed versus primed T cells. In addition, they are able to provide help for B-cell differentiation and contain substantial numbers of tetanus toxoid (TT)-specific precursor cells. Remarkably, both intracellular cytokine staining and analysis of T-cell clones showed that Ddull cells and CD45RO+ T cells produce comparable high amounts of both interferon (IFN)-gamma and interleukin (IL)-4, which clearly distinguishes them from CD45RA+ and Dbright T cells. Finally, prolonged culture of sorted Ddull cells in a mixture of IL-2, IL-6, and tumor necrosis factor (TNF)-alpha showed that about half of the population retained the Ddull phenotype. Part of the cells upregulated the CD45RA isoform, whereas only a minority switched to single CD45RO expression. Our findings indicate that the Ddull population contains primed T cells, some of which may reacquire an "unprimed" phenotype in the absence of antigenic stimulation.     

Kaposi's sarcoma (KS)-associated herpesvirus-like DNA sequences in peripheral blood mononuclear cells: association with KS and persistence in patients receiving anti-herpesvirus drugs

Herpesvirus-like DNA sequences (KSHV/HHV-8) have recently been described in AIDS-associated Kaposi's sarcoma (KS) lesions. Many questions remain regarding the role of this virus in KS and the therapeutic implications of this finding. In the current study, KSHV/HHV-8 DNA was detected in peripheral blood mononuclear cells (PBMCs) from human immunodeficiency virus (HIV)-infected patients with KS (34/98) more often than in HIV-infected individuals without KS (12/64, P = .03). The detection of KSHV/HHV-8 DNA did not correlate with the CD4 lymphocyte count. Five patients demonstrated KSHV/HHV-8 DNA in their PBMCs during administration of intravenous foscarnet and/or ganciclovir. The continued detection of KSHV/HHV-8 DNA in the PBMCs of patients receiving these anti-herpesvirus drugs has potential implications regarding the virus-cell relationship of KSHV/HHV-8, as well as for the value of these drugs in treating or preventing KS, but additional studies are needed.