Resource costing for multinational neurologic clinical trials: methods and results.

We present the results of a multinational resource costing study for a prospective economic evaluation of a new medical technology for treatment of subarachnoid hemorrhage within a clinical trial. The study describes a framework for the collection and analysis of international resource cost data that can contribute to a consistent and accurate intercountry estimation of cost. Of the 15 countries that participated in the clinical trial, we collected cost information in the following seven: Australia, France, Germany, the UK, Italy, Spain, and Sweden. The collection of cost data in these countries was structured through the use of worksheets to provide accurate and efficient cost reporting. We converted total average costs to average variable costs and then aggregated the data to develop study unit costs. When unit costs were unavailable, we developed an index table, based on a market-basket approach, to estimate unit costs. To estimate the cost of a given procedure, the market-basket estimation process required that cost information be available for at least one country. When cost information was unavailable in all countries for a given procedure, we estimated costs using a method based on physician-work and practice-expense resource-based relative value units. Finally, we converted study unit costs to a common currency using purchasing power parity measures. Through this costing exercise we developed a set of unit costs for patient services and per diem hospital services. We conclude by discussing the implications of our costing exercise and suggest guidelines to facilitate more effective multinational costing exercises.

Economic analysis of tirilazad mesylate for aneurysmal subarachnoid hemorrhage. Economic evaluation of a phase III clinical trial in Europe and Australia.

This study used data from a multinational phase III randomized, double-blind, vehicle-controlled trial to evaluate the cost-effectiveness of tirilazad mesylate (Freedox) in the treatment of aneurysmal subarachnoid hemorrhage. In men, therapy with 6 mg/kg per day of tirilazad mesylate was associated with significantly increased survival, increased cost of care, and ratios of cost per death averted that compare favorably with the ratios of other life and death interventions. In women, it appeared to have no effects on costs or survival. Further clinical studies may provide additional information about the cost-effectiveness of this intervention.

Characterization of an inhibitory factor derived from epithelial cells of the small intestine.

Rat small intestine epithelial cell (EC) culture conditioned media (ECCM) contains a factor that has inhibitory activity against: a) the response of freshly isolated lymphocytes to Concanavalin A (Con A) or IL-2, b) the proliferative response to antigen of primed lymphocytes, and c) the normal growth of transformed cell lines derived from several species. Inhibition is reversible, and not the result of a cytotoxic effect. The inhibitory activity is enterocyte derived, effective at low concentration (1-2% in growth media), and can be derived from freshly isolated EC. Biochemical analysis indicates the inhibitory activity is associated with a protein with an approximate molecular weight of 32 kd, and an isoelectric point (PI) in the range of 3-5. The protein is trypsin sensitive, and labile with prolonged heating at 56 degrees C. The described activity differs from previously reported mucosally-derived inhibitory activities on the basis of molecular weight, and its ability to inhibit the growth of several cell lines. We suggest that this factor can provide the immunomodulatory activity necessary to produce the low level of intestinal T cell reactivity that is observed in vivo.

Susceptibility to HIV-1 infection of a human B-lymphoblastoid cell line, DG75, transfected with subgenomic DNA fragments of Epstein-Barr virus.

We have previously shown that the presence of the EBV genome and active EBV infection in some Burkitt's lymphoma cell lines confer the susceptibility of HIV-1 infection in spite of the absence of surface CD4 receptors in these cells. In the present study we used an EBV genome negative Burkitt's lymphoma B-cell line, DG75, transfected with three different subgenomic fragments of EBV expressing the nuclear antigens (EBNA1 and EBNA2) and the latent membrane protein (LMP), respectively. Immunofluorescence analysis demonstrated CD4 expression in more than 90% of the EBNA1, EBNA2 and LMP transfected cell lines, whereas the antigen could only be detected in less than 4% of the parental DG75 cell line. Unlike the wild type DG75 line, the three transfected cell lines were shown to be susceptible to HIV-1 by both IFA and production of virions. Northern blotting of poly(A) selected mRNA of the four cell lines and hybridization to a human CD4 cDNA (pT4B) demonstrated a 3 kb band in all three EBNA1, EBNA2 and LMP transfected cells as well as in the wild type DG75 cells. Approximate quantification indicates equivalent level of T4 mRNA expression in the transfected cell lines as compared to T-cell lines (Hut-78, H9-9).

Utilization of human hematopoietic cell lines for the propagation and characterization of HBLV (human herpesvirus 6).

In 1986, we reported the discovery and isolation of a novel human herpesvirus (HBLV) from AIDS and other lymphoproliferative disorders. Because HBLV is distinct from other members of the herpesvirus family and can infect B- and T-lymphocytes and other human cells (megakaryocytes and glioblastoma cells), we suggested human herpesvirus-6 (HHV-6) as the taxonomic designation for this virus. In cultures from patients' peripheral blood, the evidence of HBLV can be recognized from the appearance of short-lived giant cells (2-10%), which are large, refractile, and are often mono- and binucleated. As these cells degenerate, extracellular virus particles are found in the culture medium. HBLV can infect fresh mononuclear cells, established B- and T-lymphoblastoid cell lines, megakaryocytes and glioblastoma cell lines. HBLV infection can be detected by: a. morphological changes; b. indirect immunofluorescence assay, in situ hybridization, southern blot analysis, polymerase chain reaction amplification; and c. electron microscopy. Because of its wide cell tropism, HBLV DNA sequences have been detected in B-cell lymphomas and short term cultured cells from Sjogren's patients. Expression of HBLV RNA was also detected in sarcoidosis. The etiological role of HBLV in human tumors is unclear. While in vitro data may not necessarily apply to in vivo conditions, the infection of various cell lines from tumors and fresh mononuclear cells suggests HBLV involvement in a variety of diseases.

Utilization of human hematopoietic cell lines for the propagation and characterization of HBLV (human herpesvirus 6).

Details of the productive infection of established human cell lines of diverse origin by HBLV (also designated Human Herpesvirus 6) are described in this report. The infection and replication of HBLV in several T and B lymphoid and other cell lines was observed by electron microscopic examination, by the detection of viral antigen expression by indirect immunofluorescence assay (IFA) and by the presence of HBLV DNA by Southern blot hybridization. Several of these cell lines produced large amounts of virus. For this reason and because of the absence of other human herpesviruses, these lines have provided a valuable resource for the preparation of reagents and the development of assays for the detection and characterization of HBLV. The isolation and characterization of new HBLV isolates from patients with chronic fatigue syndrome were also facilitated by using some of the cell lines reported here. The host range of HBLV in established cell lines, therefore, does not appear to be limited to the B lymphocytes, as initially suggested by in vivo studies. The infection of T and B lymphocytes, megakaryocytes and neuronal cells in vitro suggests a need for the evaluation of diverse hematological and neurological disorders to shed light on a possible HBLV involvement.

Human B-lymphotropic virus (human herpesvirus-6).

Human B-lymphotropic virus (HBLV), also known as human herpesvirus-6 (HHV-6) was first isolated in 1986 from AIDS patients and patients with other lymphoproliferative disorders. HBLV is distinct from known human herpesviruses, biologically, immunologically and by molecular analysis. HBLV can infect and replicate in fresh and established lines of hemopoietic cells and cells of neural origin, suggesting wide tropism. The prevalence of HBLV antibody in the normal population was 26% though clear differences between different populations were observed. The prevalence of HBLV antibody an elevated antibody titer was higher in sera from certain malignancies, Sjögren's syndrome and sarcoidosis. Antibody to HBLV was also elevated in AIDS patients and patients with chronic fatigue syndrome. HBLV-DNA was detected in some B-cell lymphomas. The broad in vitro tropism, combined with immunological and molecular evidence of HBLV infection in individuals raise the question of the pathogenicity of this virus in some diseases. Because in vitro co-infection of CD4 cells by HBLV and HIV leads to enhanced degeneration, this raises the possibility that infection in AIDS patients by both viruses can aggravate the HIV-induced immunodeficiency. Specific reagents and immunological and molecular assays are currently being investigated, which will aid in virus detection in cells from patients, and in elucidating the possible pathogenesis of HBLV.