Evaluation of the COBAS ampliprep/COBAS TaqMan system for quantification of human immunodeficiency virus type 1 (HIV-1) RNA by real-time PCR

BACKGROUND: Viral load quantification is standard for monitoring HIV-1 therapy and is crucial in deciding whether to switch or to continue a current antiretroviral regimen. In Japan, serum is widely adapted as a specimen of the HIV-1 viral load quantification assay. METHODS: We evaluated an emerging HIV-1 RNA quantification of the COBAS AmpliPrep/COBAS TaqMan HIV-1 Test (COBAS TaqMan). The test was evaluated for matrix equivalence between plasma and serum and for correlation with the AMPLICOR HIV-1 Monitor Test v1.5 (Amplicor) for HIV-1 RNA quantification. RESULTS: The test result from serum specimens showed good correlation with test results from plasma specimens. HIV-1 RNA quantification results using serum specimens correlated well with those obtained by both ultrasensitivity assay and standard Amplicor assay. CONCLUSIONS: The fully automated COBAS AmpliPrep/COBAS TaqMan HIV-1 Test meets requirements for a wide dynamic range and reliable quantification of HIV-1 RNA in serum clinical specimens.     

The role of neutrophil membrane glycoprotein GP-150 in neutrophil adherence to endothelium in vitro

We have previously described two patients with a congenital defect in neutrophil function characterized by an inability to form pus. The patients' neutrophils lack a membrane glycoprotein of mol wt 150,000 daltons (GP-150) on analysis by SDS-PAGE. This glycoprotein is part of a membrane antigen complex recognized by the murine monoclonal antibody (MoAb) 60.3. Addition of MoAb 60.3 to normal neutrophils produces defects in chemotaxis and phagocytosis in vitro similar to those observed in the patients. Since neutrophil adherence to vascular endothelium is prerequisite to neutrophil emigration in vivo, we examined the interaction of the patients' neutrophils and normal neutrophils treated with MoAb 60.3 with cultured endothelium. Adherence was determined as the percentage of 51Cr-labeled purified peripheral blood neutrophils which remained adherent to plastic wells or endothelial monolayers after a 45-minute incubation at 37 degrees C. The percentage of neutrophils from patient 1 remaining adherent to uncoated, fibronectin-coated, or laminin-coated plastic was similar to that observed in normal neutrophils (55% to 84% adherence with normal neutrophils v 73% to 78% adherence with the patient's neutrophils and 63% to 82% adherence with MoAb 60.3-treated normal neutrophils). The adherence of the neutrophils from patient 1 and MoAb 60.3-treated normal neutrophils to human or bovine endothelium in serum-free medium was also not significantly different from that observed in normal neutrophils (less than 10% adherence with normal, MoAb 60.3-treated, and patient neutrophils). In medium containing 10% autologous or heterologous human plasma, however, the adherence of neutrophils from patient 1 or MoAb 60.3-treated normal neutrophils to endothelial monolayers was significantly reduced (35% +/- 7% of normal neutrophils in seven experiments). Although phorbol myristate acetate (PMA) (10 ng/mL) and calcium ionophore A23187 (10(-5) mol/L) markedly increased the adherence of normal neutrophils to endothelial monolayers in serum- free medium (40% to 85% adherence), neither agent increased the adherence of the neutrophils from patient 1 or normal neutrophils treated with MoAb 60.3 (less than 5% adherence). The adherence of PMA- activated neutrophils from patient 2 to endothelial monolayers was also markedly decreased when compared with that of normal neutrophils. Postsecretory cell-free supernatants from PMA-activated normal neutrophils failed to augment adherence of neutrophils from patient 1 (less than 5% adherence).(ABSTRACT TRUNCATED AT 400 WORDS)     

Interleukin-3 and interleukin-7 are alternative growth factors for the same B-cell precursors in the mouse

Clones and lines of precursor (pre) B cells can be established by limiting dilutions of unseparated cell suspensions of fetal liver or bone marrow on stromal cells in the presence of interleukin (IL)-7. When IL-3 is used instead of IL-7, cultures are regularly overgrown by different precursor cells of the myeloid lineage, as well as by adherent cells that inhibit pre-B-cell expansion. However, in the presence of either IL-7 or IL-3, clones of pre-B cells can be established on stroma cells at frequencies near one in one when the cultures are initiated with cell sorter purified CD45RO (B220)+/c-kit+ fetal liver or bone marrow derived pre-B cells. Clones grown on stromal cells in the presence of IL-7 can be regrown in IL-3, and vice versa. Pre-B cells that proliferate on stromal cells in the presence of IL-7 or IL-3 have the same phenotype, ie, are B220+ c-kit+, CD43+, and surrogate light chain+. Removal of the growth factors (IL-7, respectively IL-3) from the cultures results in differentiation to surface immunoglobulin (slg) positive, c-kit-, CD43-, surrogate light chain- B cells, a fraction of which is lipopolysaccharide (LPS) responsive as shown by IgM secretion. These results show that IL-7 and IL-3 stimulate largely overlapping populations of precursor B cells from bone marrow to proliferate for long periods of time in the presence of stromal cells. Thus, IL-7 and IL-3 are alternative growth factors for the same pre-BI cell.     

Localization of factor VIII-procoagulant antigen: an immunohistological survey of the human body using monoclonal antibodies

Various organs, including liver, spleen, heart, lung, kidney, intestines, lymph nodes, pancreas, bone marrow, and thymus, were investigated for the presence of factor VIII-procoagulant antigen (VIIICAg) and factor VIII-related antigen (VIIIRAg), using a panel of monoclonal antibodies directed to factor VIII-von Willebrand factor in combination with a sensitive immunoperoxidase staining technique. In addition to hepatic sinusoidal endothelial cells, the presence of VIIICAg was demonstrated in mononuclear cells sporadically present in lymph nodes, in the alveolar septa of lung, and in the red pulp of spleen. The identity of these mononuclear cells could not be unequivocally determined. Based on morphological criteria, however, it is tentatively concluded that these cells are nonlymphoid and belong to the mononuclear phagocyte system. The presence of VIII-RAg was confined to vascular endothelial cells, hepatic sinusoidal endothelial cells, cells lining the venous sinuses of the red pulp of the spleen, cells lining renal glomeruli and lung capillaries, platelets, and megakaryocytes.     

Characterization of 25 monoclonal antibodies to factor VIII-von Willebrand factor: relationship between ristocetin-induced platelet aggregation and platelet adherence to subendothelium

We have studied the role of factor VIII-von Willebrand factor (FVIII- vWF) in both platelet adherence to subendothelium and ristocetin- induced platelet aggregation using monoclonal antibodies to human FVIII- vWF. Twenty-five monoclonal antibodies were obtained, two of which were directed to the factor VIII moiety of FVIII-vWF; one of these two completely inhibited the procoagulant activity (FVIII:C). The remaining 23 monoclonal antibodies were directed to the von Willebrand factor moiety of FVIII-vWF. The ability of the latter monoclonal antibodies to inhibit platelet adherence to arterial subendothelium was investigated with a perfusion model. According to the number of platelets adhering to the subendothelium, three groups of monoclonal antibodies could be discerned: (A) antibodies not affecting platelet adherence; (B) antibodies that inhibited platelet adherence to the level as observed when von Willebrand's disease plasma was tested; and (C) antibodies that completely inhibited both platelet adherence to subendothelium and ristocetin-induced platelet aggregation. The two antibodies present in group C competed for the same or closely related epitope(s) present on FVIII-vWF. These results demonstrate that a domain is present on the FVIII-vWF molecule that is associated both with ristocetin-induced aggregation and with the ability of FVIII-vWF to support platelet adherence to the subendothelium. Based on these observations, it is concluded that ristocetin-induced binding of FVIII-vWF to platelets reflects, at least in part, a physiologic mechanism regulating the function of FVIII-vWF in primary hemostasis.     

The rare alpha-thalassemia-1 of blacks is a zeta alpha-thalassemia-1 associated with deletion of all alpha- and zeta-globin genes

Restriction endonuclease mapping with alpha and zeta-globin gene probes showed differences between the alpha-thalassemia-1 (alpha-thal-1) condition in two patients with HbH disease. One patient had the rare black type of alpha-thal-1 together with alpha-thal-2 and HbS heterozygosities. The second patient was a Laotian child with HbE, Hb Constant Spring (alpha-thal-2), and alpha-thal-1 heterozygosities. The diagnoses were based on clinical, hematologic, and biochemical data. Whereas DNA fragments hybridizing to a zeta-probe were obtained from the Laotian type of alpha-thal-1, neither alpha nor zeta-gene fragments could be identified deriving from the black type of alpha-thal-1. Therefore, the black type of alpha-thal-1 is associated with a deletion of the entire zeta 2-psi zeta-psi alpha-alpha 2-alpha 1 gene complex and can be considered a zeta alpha-thal-1. It is likely that homozygosity for such a condition will lead to embryonic wastage, explaining the absence of hydrops fetalis in blacks.     

Frequency of immediate adverse effects associated with apheresis donation

BACKGROUND: Apheresis donation is considered safe, but the incidence of adverse effects has not been determined in a large multicenter series of donations with modern instruments. STUDY DESIGN AND METHODS: The Hemapheresis Committee of the American Association of Blood Banks devised a uniform questionnaire that asked about 32 specific adverse effects. Transient paresthesia and mild vasovagal events were excluded. A survey was conducted in 1995; 17 centers returned 19,611 responses concerning 250 to 2,000 consecutive apheresis donations per center. RESULTS: Six hundred adverse effects were reported in 428 donations (2.18% of donations). Pain or hematoma at a venipuncture site was the most common response (1.15% of donations); only 203 donations had other (nonvenipuncture) adverse effects (1.04%). Total and nonvenipuncture rates were, respectively, 4.84 and 2.92 percent for 2,295 first donations and 1.78 and 0.77 percent for 17,303 repeat donations (p < 0.001). Rates of nonvenipuncture symptoms in first and repeat donations were, respectively, citrate-induced nausea and/or vomiting, 0.87 and 0.27 percent; tetany, 0.09 and 0.04 percent; pallor and/or diaphoresis, 1.87 and 0.32 percent; vasovagal nausea and/or vomiting, 0.87 and 0.13 percent; syncope and/or seizure, 0.39 and 0.04 percent; and chills and/or rigors, 0.31 and 0.01 percent. The overall rate of donor unconsciousness was 0.08 percent. Hemolysis was reported twice. Clotting or leakage occurred in 0.08 percent of donations, and inability to return blood occurred in 0.16 percent. No life-threatening adverse effects were reported. Procedure-specific nonvenipuncture rates were 1.05 percent of 17,584 platelet donations, 0.67 percent of 594 white cell donations, and 0.37 percent of 1,354 plasma donations. Center-specific rates varied from 0.32 to 6.81 percent of donations for total adverse effects and from 0.11 to 2.92 percent of donations for nonvenipuncture events. CONCLUSION: Apheresis donation is a safe undertaking, suitable for voluntary blood donors, with a very low risk of serious adverse effects. The risk of unconsciousness is lower than that found in many studies of whole-blood donation.     

A comparative trial of granulocyte-colony-stimulating factor and dexamethasone, separately and in combination, for the mobilization of neutrophils in the peripheral blood of normal volunteers

BACKGROUND: The clinical utility of polymorphonuclear neutrophil (PMN) transfusion therapy has been compromised, in part, by the inability to obtain sufficient quantities of functional neutrophils from donors. To define the optimal conditions for mobilization of PMNs in granulocyte donors, the effects of granulocyte-colony-stimulating factor (G-CSF) and dexamethasone, separately and in combination, on PMN counts in normal volunteers were compared. STUDY DESIGN AND METHODS: Five normal subjects were randomly assigned to each of the following single-dose regimens in 5 consecutive weeks: 1) G-CSF, 300 micrograms given subcutaneously; 2) G-CSF, 600 micrograms subcutaneously: 3) dexamethasone, 8 mg given orally; 4) G-CSF, 300 micrograms subcutaneously, plus dexamethasone, 8 mg orally; and 5) G-CSF, 600 micrograms subcutaneously, plus dexamethasone 8 mg orally. Venous blood was collected at 0, 6, 12, and 24 hours after drug administration for the determination of absolute neutrophil counts (ANCs). RESULTS: Maximal ANC was achieved at 12 hours after each regimen, except dexamethasone alone (maximum, 24 hours). Dexamethasone significantly increased the maximal ANC induced by either dose of G-CSF alone (p < 0.05). The greatest mobilization of PMNs occurred after the administration of G-CSF (600 micrograms) and dexamethasone (8 mg); the ANC increased from a mean baseline value of 3,594 per microL to 43,017 per microL at 12 hours. All of the drug regimens were well tolerated. CONCLUSION: Dexamethasone significantly increases the level of neutrophilia induced in normal subjects by G-CSF. The combination of dexamethasone and G-CSF (at the dosages used in this study) is a convenient, well-tolerated regimen for the mobilization of PMNs in the peripheral blood of granulocyte donors. Moreover, the optimal quantitative yield of PMNs is likely to be achieved by leukapheresis 12 hours after drug administration.     

COR TRIATRIATUM: UNUSUAL CAUSE OF TRANSIENT ISCHAEMIC ATTACKS IN A 67-YEAR-OLD MAN

SUMMARY Cor triatriatum is a rare congenital cardiac malformation, and in its most common form is characterised by a membrane that separates the left atrium into a proximal and distal chamber. First manifestation in adulthood has been reported previously, but at 67 years of age this patient is one of the oldest to present for the first time. It was diagnosed after a probable TIA, episodic vertigo and central retinal artery occlusion. The value of echocardiography in patients with neurological disease of presumed embolic origin is demonstrated here.     

Rapid freezing of whole blood or buffy coat samples for polymerase chain reaction and cell culture analysis: application to detection of human immunodeficiency virus in blood donor and recipient repositories. The Transfusion Safety Study Group

Storage of lymphocytes for later use in prospective epidemiologic studies of blood donors and transfusion recipients has been limited by the cost of separating peripheral blood mononuclear cells (PBMCs). When the Transfusion Safety Study began in 1985, it was decided to establish a cell repository of cryopreserved buffy coat (BC) samples, and thus far over 20,000 samples have been accumulated from enrolled subjects. To determine if these specimens could be used for polymerase chain reaction, a simple thawing and pelleting technique for recovering hemoglobin-free total white cells (WBCs) was developed. To validate the technique, parallel analysis was conducted of BCs, whole blood (WB), and PBMC samples from human immunodeficiency virus type 1 (HIV-1)- seropositive subjects. Immediate postthaw cell courts of 29 frozen- thawed (F-T) WB and BC samples averaged 90 percent of the prefreeze (input) values. Representative WBC populations were obtained by immediate pelleting. Amplification of HIV-1 gag sequences from F-T BCs and F-T WB was 94 and 75 percent, respectively, which is as sensitive as that obtained with freshly separated PBMC lysates. Quantitative HIV- 1 proviral load analysis by serial dilution of 23 F-T BCs and 8 WB lysates showed results comparable to those obtained with lysates of fresh PBMCs. Values for WBC differential and immunophenotyping could be applied to express viral load relative to total WBCs, PBMCs, or CD4+ cells. These results establish the basis for simplified virologic analysis of cryopreserved BC or WB specimens.