Investigation of laminar appearance of articular cartilage by means of magnetic resonance microscopy

Magnetic resonance (MR) images and relaxation and diffusion maps of articular cartilage were obtained to explain discrepancies in its MR appearance. Porcine specimens were studied only by MR microscopy. For human specimens a combination of MR microscopy and large-scale MR imaging was used. Common features in the laminar structures of human and porcine samples are described. It was found that the decay of transverse magnetization was nonexponential with a rapidly decaying component which prevented construction of reliable proton-density maps. Dependence of T2 values on the orientation of specimens in the magnetic field as well as magnetization transfer experiments supported the previous suggestions about a significant role of dipolar interaction with protons of collagen in the laminar appearance of articular cartilage. The loss of the laminar structure induced by rotation of the human cartilage specimen around the axis normal to its surface demonstrated nonuniform angular distribution of the collagen fibers within the layer.

Age-associated changes in CD8+ and CD16+ cell reactivity: clonal analysis

A cloning technique was used to estimate the frequency of proliferating T cell precursors, the growth capacity of clone-forming cells and the functional activity of clones established in vitro from peripheral blood lymphocytes of young and old people. The mean frequency of proliferating precursors was lower in the elderly as was the proliferative capacity of CD8+ clones. In contrast, CD4+ and CD16+ clones showed a proliferation similar to that obtained from young subjects. When the clones were examined for their functional activity, CD4+ clones from both groups failed to show any cytolytic activity, while CD8+ clones exerted cytolysis against K562 and in antibody-dependent cell-mediated cytotoxicity but this function was reduced in clones derived from old subjects. Similarly, CD16+ clones from the elderly showed a decreased activity at some effector-to-target cell ratios. We conclude that the impaired functional activity (T or NK-dependent) found in the peripheral blood of aged subjects persists after in vitro selection when these cells are analysed at clonal level.

Immunohistopathological and neuroimaging characterization of murine orthotopic xenograft models of glioblastoma multiforme recapitulating the most salient features of human disease

Tumorigenesis in human glioblastoma multiforme (GBM) is driven by several genetic abnormalities with disruption of important molecular pathways, such as p53/MDM2/p14ARF and EGFR/PTEN/Akt/mTOR. The malignant progression of human GBM is also primarily associated with a peculiar multistep pathophysiological process characterized by intratumoral ischemic necrosis (i.e. pseudopalisading necrosis) and activation of the hypoxia-inducible factor (HIF)-1alpha pathway with consequent peritumoral microvascular proliferation and infiltrative behaviour. Predictable preclinical animal models of GBM should recapitulate the main pathobiological hallmarks of the human disease. In this study we describe two murine orthotopic xenograft models using U87MG and U251 human cell lines. Ten Balb/c nude male mice were orthotopically implanted with either U87MG (5 mice) or U251 (5 mice) cell lines. Intracranial tumor growth was monitored through Magnetic Resonance Imaging (MRI). Immunohistopathological examination of the whole cranium was performed 30 days after implantation. U251 orthotopic xenografts recapitulated the salient pathobiological features described for human GBM, including invasive behaviour, wide areas of pseudopalisading necrosis, florid peripheral angiogenesis, GFAP and vimentin expression, nonfunctional p53 expression, striking active-caspase-3 and HIF-1alpha expression along pseudopalisades. U87MG orthotopic xenografts proved to be very dissimilar from human GBM, showing expansile growth, occasional necrotic foci without pseudopalisades, intratumoral lacunar pattern of angiogenesis, lack of GFAP expression, functional p53 expression and inconsistent HIF-1alpha expression. Expression of pAkt was upregulated in both models. The results obtained suggest that the U251 orthotopic model may be proposed as a predictive and reliable tool in preclinical studies since it recapitulates the most salient pathobiological features reported for human GBM.

Oxygen-derived free radical (ODFR) action on hyaluronan (HA), on two HA ester derivatives, and on the metabolism of articular chondrocytes

Oxygen-derived free radicals (ODFR) appear to be involved in the pathogenesis of arthritic disorders. In order to gain new insight on their role in the phenomenon and as a basis for a therapeutic approach, the effect of ODFR (produced by the xanthine oxidase-hypoxantine system) on hyaluronic acid, on two HA ester derivatives, and on pig articular chondrocytes was investigated. High M(r) HA (1.1 x 10(6)) and low M(r) HA (16 x 10(4)) were depolymerized by ODFR but the methyl and hydrocortisone esters of HA (HYAFF 2P50 and HYC13) turned out to be nearly unaffected. When articular chondrocytes were treated with ODFR, a rapid nucleoside triphosphate (NTP) depletion, a transient appearance of pyrophosphate (PPi), and an increase of phosphomonoester and diphosphodiester concentrations have been observed. The NTP depletion and the DPDE increase are related to the concentration of free radicals. Glyceraldehyde-3-phosphate accumulation during ODFR treatment suggests that ATP depletion can occur as a consequence of the blockage of glycolysis at the level of glyceraldehyde-3-P dehydrogenase. The hypothesis is presented that PPi can be produced from the pathway of the FAD-NAD (DPDE) biosynthesis and then either hydrolyzed by endogenous pyrophosphatases or precipitated in the form of insoluble calcium salts. Long-term treatment (16 h) with ODFR causes a loss of chondrocyte membrane integrity which can be revealed both by an increased free LDH activity and by the characteristic signal of free phospholipids in the 31P-NMR spectra. While high M(r) HA shows a significant protective activity for chondrocytes against ODFR action, low M(r) HA and ester derivatives do not. It is suggested that the therapeutic activity of HA ester derivatives can be ascribed to their in vivo hydrolysis products.

In vitro culture of primary plasmacytomas requires stromal cell feeder layers

Attempts to grow primary murine plasmacytomas in vitro have, to date, been largely unsuccessful. In this study, we demonstrate that long-term in vitro growth of primary plasmacytomas is accomplished by using feeder layers composed of stromal cells from the initial site of plasmacytomagenesis. The early neoplastic lines established in this manner are dependent on physical contact with the stromal layer, which is mediated in part by CD44, for growth and survival. The stromal cells provide at least two stimuli for the plasma cells, one being interleukin 6 and the second, of unknown nature, resulting from direct physical interaction that cannot be replaced by soluble factors. These plasma cell lines have been passaged for as long as 20 months yet still maintain characteristics associated with primary plasmacytomas as they will grow in vivo only in pristane-primed animals, indicating a continued dependence on the pristane-induced microenvironment characteristic of early-stage tumors. The ability to grow primary plasmacytomas in culture and maintain their "primary" properties provides a model system for detailed analysis of early events in plasma cell tumor progression involving neoplastic cells completely dependent on physical contact with a stromal feeder layer for survival and expansion.

A method for generating magnetic resonance microimaging T2 maps with low sensitivity to diffusion

Generating T2 maps in magnetic resonance microimaging is often complicated by the self-diffusion of water molecules. A modification of the standard spin-echo pulse sequence is proposed which minimizes this effect. Experiments with doped water confirmed that the T2 values obtained with the modified sequence were equal within the experimental error to the value obtained by the spectroscopic Carr-Purcell-Meiboom-Gill method. The applicability of the technique is demonstrated by generating T2 maps of porcine articular cartilage.

In vitro cultured stromal cells from human tonsils display a distinct phenotype and induce B cell adhesion and proliferation

Peripheral lymphoid tissues contain a fibroblastic cell type referred to as stromal cells or reticulum cells which interact with lymphocytes as part of the lymphoid microenvironment. After isolation from human tonsils and expansion in vitro we analyzed the surface phenotype, extracellular matrix components, cytoskeletal products, cytokine production, binding and functional interaction with B lymphocytes of in vitro cultured stromal cells (HTSC) both in resting condition and after activation with tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma. Our results show that HTSC do not express specific myeloid, lymphoid, endothelial or epithelial markers. HTSC express CD54 (ICAM-1), CD49a (VLA-1), CD49b (VLA-2), CD49c (VLA-3), CD49e (VLA-5), CD49f (VLA-6), CD29, CD51, CD44 and produce vinculin, beta-tubulin, alpha-actin, vimentin, fibronectin, laminin and collagen types I, III and IV. Activation of HTSC up-regulated CD54 (ICAM-1) and induced HLA-DR and CD106 (VCAM-1). HTSC constitutively produce interleukin (IL)-6 which is enhanced upon activation with TNF-alpha. IL-8 and granulocyte/macrophage colony-stimulating factor are detected only in the supernatants of activated HTSC. Reverse transcriptase polymerase chain reaction analysis revealed that HTSC display mRNA for IL-1 alpha, leukemia inhibitory factor and IL-7. The adhesion of tonsillar B lymphocytes to activated HTSC is mediated by CD11a/CD18 and CD54. Furthermore, HTSC can induce maximal proliferation of IL-2-activated B lymphocytes cocultured in direct cell-cell contact with HTSC. These results clearly distinguish in vitro cultured HTSC from common fibroblasts and other non-lymphoid elements present in the lymphoid parenchyma, such as follicular dendritic cells, and show that HTSC actively participate in the lymphoid microenvironment. In vitro cultures of HTSC could therefore be a useful model system for detailed analysis of the interactions between stromal cells and lymphocytes under physiological and pathological conditions.

Evaluation of ex vivo expansion and engraftment in NOD-SCID mice of umbilical cord blood CD34+ cells using the DIDECO "Pluricell System"

The Dideco "Pluricell System" is a commercially available closed device composed of an expansion chamber and a kit of certified reagents that allow haematopoietic stem cell expansion. We have expanded seven umbilical cord blood (UCB) samples following the manufacturer's instructions; two groups of irradiated NOD-SCID mice have been transplanted with expanded and nonexpanded cells from the same UCB, and bone marrow was analysed for the presence of human cells. Average UCB volume was 61.6+/-8.8 ml; mean nucleated cell content was 1090.5+/-189.9 x 10(6). Percentage and number of CD34+ cells were 0.37+/-0.13% and 3.9+/-1.2 x 10(6). After separation, CD34+ cell purity was 82+/-11%. Mean number of inoculated cells was 760 000; mean NC and CD34+ fold expansion at 12 days was 230.4+/-91.5 and 21.0+/-11.9. Both groups of mice showed successful engraftment: the percentage of human cells was higher in the group receiving expanded cells (3.4+/-2.01%) compared to the group receiving nonexpanded cells (1.5+/-0.66%) (P<0.00018, Mann-Whitney test). The cell population obtained after 12 days expansion consisted mainly of myeloid and megakaryocytic progenitors. The CD34+ antigen reached the maximum expression level at day 12 (7.5+/-2.0%). Analysis of lineage-markers for human myelomonocytic, megakaryocytic, B, T, CD34 and erythroid cells, gave evidence that all the lineages were represented in the marrow of transplanted mice.

Phenotypic characterization of immunomagnetically purified umbilical cord blood CD34+ cells

This study describes the multilineage differentiation pattern of purified CD34+ stem cells obtained from human umbilical cord blood. CD34+ cells were collected from 49 umbilical cord blood samples. Following immunomagnetic purification, cells were double stained with anti CD34 and CD71, CD61, CD7, CD19, CD33, CD36 and triple stained with anti CD34, CD38 and HLA-DR. Analysis were performed using a FACScan flow cytometer. After purification, the mean CD34+ cells' purity was 85.49 +/- 7.08%. Several subpopulations of umbilical cord blood CD34+ cells were identified indicating different lineage commitment. The majority of CD34+ cells expressed both CD38 and HLA-DR (91.74 +/- 3.76%), while those lacking CD38 were 3.43 +/- 2.12% (CD38-DR+) and 1.81 +/- 1.54% (CD38-DR-). These data were compared to the expression of lineage commitment markers on purified CD34+ cells from 5 mobilized peripheral blood samples. The percentage of peripheral blood CD34+CD38-DR+) and CD34+CD38-DR- cells was significantly lower than umbilical cord blood, 0.24 +/- 0.18% and 0.04 +/- 0.03% respectively. The knowledge and standardized of umbilical cord blood CD34+ cells phenotype is critical since umbilical cord blood volume is limited. The homogeneity of CD34+ subpopulation phenotype suggests that monitoring of lineage differentiation antigens may not be relevant for clinical use of umbilical cord blood samples. However, the observed higher percentage of pluripotent CD34+38- stem cells in umbilical cord blood compared to peripheral blood, that might explain the successful clinical use of umbilical cord blood even when low number of cells are used, candidates these antigens as the predictive parameter for clinical use of umbilical cord blood samples.

A fluorescent in situ hybridization method in flow cytometry to detect HIV-1 specific RNA

In HIV+ patients, the presence of HIV-RNA in plasma and circulating cells has been reported to be a marker of progression but the percentage of transcriptionally active infected cells remains unclear. We have developed a reliable fluorescent in situ hybridization method for the detection of HIV specific RNA by flow cytometry. The procedure was applied to a panel of chronically infected cell lines and to an acutely infected cell line mimicking normal peripheral blood lymphocytes in susceptibility to HIV-1. The cells were fixed in suspension and hybridized by means of an HIV-1 genomic probe labeled with digoxigenin-11-dUTP. An FITC-labeled anti-digoxigenin antiserum was then applied and the resulting fluorescence signals were analyzed both by flow cytometry and confocal microscopy. Different procedures for double staining HIV-RNA together with virus induced proteins or surface markers were also developed. Flow cytometric detection of in situ hybridization offers the possibility of analyzing thousands of cells in a few seconds and of collecting multiparametric information at the single cell level, thus providing a potential tool for detecting the rare HIV-RNA expressing cells in peripheral blood samples.

Anti-tumour efficacy on glioma models of PHA-848125, a multi-kinase inhibitor able to cross the blood-brain barrier

BACKGROUND AND PURPOSE

Malignant gliomas, the most common primary brain tumours, are highly invasive and neurologically destructive neoplasms with a very bad prognosis due to the difficulty in removing the mass completely by surgery and the limited activity of current therapeutic agents. PHA-848125 is a multi-kinase inhibitor with broad anti-tumour activity in pre-clinical studies and good tolerability in phase 1 studies, which could affect two main pathways involved in glioma pathogenesis, the G1-S phase progression control pathway through the inhibition of cyclin-dependent kinases and the signalling pathways mediated by tyrosine kinase growth factor receptors, such as tropomyosin receptors. For this reason, we tested PHA-848125 in glioma models.

EXPERIMENTAL APPROACH

PHA-848125 was tested on a panel of glioma cell lines in vitro to evaluate inhibition of proliferation and mechanism of action. In vivo efficacy was evaluated on two glioma models both as single agent and in combination with standard therapy.

KEY RESULTS

When tested on a subset of representative glioma cell lines, PHA-848125 blocked cell proliferation, DNA synthesis and inhibited both cell cycle and signal transduction markers. Relevantly, PHA-848125 was also able to induce cell death through autophagy in all cell lines. Good anti-tumour efficacy was observed by oral route in different glioma models both with s.c. and intracranial implantation. Indeed, we demonstrate that the drug is able to cross the blood-brain barrier. Moreover, the combination of PHA-848125 with temozolomide resulted in a synergistic effect, and a clear therapeutic gain was also observed with a triple treatment adding PHA-848125 to radiotherapy and temozolomide.

CONCLUSIONS AND IMPLICATIONS

All the pre-clinical data obtained so far suggest that PHA-848125 may become a useful agent in chemotherapy regimens for glioma patients and support its evaluation in phase 2 trials for this indication.

Increased blood volume and CD34(+)CD38(-) progenitor cell recovery using a novel umbilical cord blood collection system

A major problem with the use of umbilical cord/placental blood (UCB) is the limited blood volume that can be collected from a single donor. In this study, we evaluated a novel system for the collection of UCB and analyzed the kinetics of output of hematopoietic stem cells in the collected blood. Sequential UCB fractions were collected from 48 placentas by gravity following common procedures. When UCB flow was ended, collection was continued using the device. Nucleated cell (NC) density in each fraction was evaluated and the expression of CD34, CD38 and other hematopoietic markers was assessed by flow cytometry. The total collected volume was 60.9 +/- 26.2 ml (mean +/- SD, range 17-141.5). The device yield (volume collected using the device/total volume) was 26.5 +/- 15.1%. No significant difference was observed in NC count in sequential fractions. A significant increase in CD34(+) cell content in sequential fractions and a 2.07 +/- 1.18-fold increase in the percentage of CD34(+) cells in the last versus first fraction were observed. Furthermore, within the CD34(+) population, the percentage of CD38(-) pluripotent stem cells in the first fraction was 3.24 +/- 1.39, while in the last fraction it raised to 34.43 +/- 22.62. Thus, at the end of a collection performed following current procedures, further blood rich in the most primitive progenitor cells can be recovered. Therefore, the optimization and standardization of collection procedures are required to obtain maximal recovery from each placenta and increase the percentage of UCB units suitable for clinical use.

In vitro immunotoxicity of +/- 2'-deoxy-3'-thiacytidine, a new anti-HIV agent

The present study compares the in vitro effect of (+/-)-2'-deoxy-3'-thiacytidine (BCH 189) a new synthetic anti-HIV-1 dideoxynucleoside, with 3'-azido-3'-deoxythymidine (AZT) on the immune function of lymphocytes from 10 normal and 12 HIV-1+ patients (CDC II and III). The effect of different doses of BCH 189 and AZT was analysed in vitro on: (i) T cell proliferation after stimulation with concanavalin A (Con A) or anti-CD3 MoAb; (ii) B cell proliferation and immunoglobulin production after stimulation with pokeweed mitogen (PWM); (iii) cytokine production (IL-2, IL-6, GM-CSF, tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) from lymphocytes stimulated with anti-CD3 MoAb or phytohaemagglutinin (PHA). BCH 189 inhibited the proliferation of B and T lymphocytes from normal and HIV+ subjects less than AZT; even if lymphocytes from HIV+ (CDC III) subjects produced higher levels of IL-6 and TNF-alpha, neither BCH 189 nor AZT molecule interfered with cytokine release. Immunoglobulin production from B lymphocytes was inhibited only by a high concentration (50 microM) of BCH 189 or AZT. These results show that BCH 189 affects lymphocyte proliferation in vitro less than AZT, and support its use in clinical trials in HIV-infected patients.

Pristane induces an indomethacin inhibitable inflammatory influx of CD4+ T cells and IFN-gamma production in plasmacytoma-susceptible BALB/cAnPt mice

In BALB/cAnPt (BALB/c) mice, the intraperitoneal injection of pristane induces the formation of chronic oil granulomatous tissue and a high incidence of plasmacytomas (PCT). DBA/2N (DBA) and (BALB/c x DBA)F1 hybrid (CDF1) mice develop oil granulomas but no PCT. Recent studies comparing pristane-injected conventionally housed BALB/c mice with specific pathogen-free BALB/c mice (SPF) demonstrated a significant reduction in both the incidence of PCT and the T cell infiltration of oil granulomatous tissue in SPF mice. In this study, FACS analysis was performed to determine the proportion of myeloid, T. and B cells present in pristane-induced peritoneal exudate (PE), and oil granulomas (OG) of BALB/c, DBA, and CDF1 mice. At all time points studied, the majority of cells recovered from the PE and OG of all three strains of mice were Mac-1+, presumably macrophages and neutrophils. Neither Ly-5(B220)+ B cells nor CD8+ T cells were significantly altered by pristane injection. BALB/c mice had a dramatic influx of CD4+ T lymphocytes (three- to fivefold) more than 50 days after the initial injection of pristane. The PCT-resistant DBA and CDF1 mice did not. This increase in CD4+ cells in BALB/c mice was not significantly affected by a second injection of pristane nor was it induced by a second injection in DBA mice. Indomethacin, which has been shown to prevent the development of PCT in BALB/c mice, prevented the infiltration of CD4+ T cells. In addition, pristane-induced levels of interferon-gamma greater than controls were found in the peritoneal lavages of BALB/c mice at all time points tested but not in DBA or indomethacin-treated BALB/c mice. In contrast, pristane injection increased levels of interleukin-5 in DBA but not BALB/c mice.

Corticotropin-releasing factor, urocortin and endothelin-1 stimulate activin A release from cultured human placental cells

Human placenta produces activin A, a glycoprotein belonging to the transforming growth factor beta superfamily, which modulates several placental immune and endocrine functions. However, substances involved in controlling placental activin A production are not yet completely elucidated. The aim of the present study was to investigate the effects of placental products, corticotropin-releasing factor (CRF), urocortin, prostaglandin E(2) (PGE(2)) and endothelin-1 (ET-1) on activin A release from cultured human placental cells. Placental tissue was collected at term from normal pregnancies and a trophoblast-enriched cell preparation was cultured for 48 h. The test substances were applied (concentration from 10(-9)-10(-7)M) and the medium was harvested after 3 h incubation; vehicle-treated cells (controls) were present in each experiment. Activin A concentrations in culture medium were measured by using a specific two-site enzyme immunoassay. The addition of CRF resulted in a dose-related increase of activin A concentrations (P < 0.01). The stimulatory effect of CRF was significantly reversed by alpha-helical CRF(9-41), the CRF receptor antagonist. Urocortin showed a stimulating effect on activin A release from placental cells (P < 0.05) but not dose-related; the effect of urocortin was reversed by an equimolar dose of CRF antagonist, astressin. ET-1 significantly increased activin A concentrations in the culture medium only at the highest concentration, 10(-7)M (P < 0.05). No difference in activin A release was observed after incubating the cells with PGE(2). The evidence that CRF, urocortin and ET-1 stimulate activin A secretion from cultured placental cells suggests that these vasoactive factors may affect the changes of placental activin A secretion in pre-eclamptic woman.

A new oxygenator change-out system and procedure

Official reports relate that, in the US, one patient/month dies as a result of the emergency oxygenator change-out procedure, and the permanent injury of some patients is the result of current oxygenator change-out procedures or oxygenator failures, both in extracorporeal circulation (ECC) and extracorporeal membrane oxygenation (ECMO).

The aim of this article is to evaluate a new system and procedure, dedicated to oxygenator change-out, represented by two three-way stopcocks inserted in the ECC line in use. A dedicated back-up oxygenator and circuit can be easily primed and connected to the dedicated connector on the stopcocks, then blood flow is diverted to the new oxygenator without interruption of the ECC.

Tests performed showed that oxygenator change-out can be completed by perfusionists in 62.139+11.12 sec. Results obtained show that the new system and procedure allows fast, safe and reproducible oxygenator change-out without interruption of the ECC.

A novel protocol that allows short-term stem cell expansion of both committed and pluripotent hematopoietic progenitor cells suitable for clinical use

To obtain long-term engraftment and hematopoiesis in myeloablated patients, the cell population used for hematopoietic reconstitution should include a sufficient number of early pluripotent hematopoietic stem cells (HSCs), along with committed cells from the various lineages. For this purpose, the small subset of CD34+ cells purified from different sources must be expanded ex vivo. Since cytokines may induce both proliferation and differentiation, expansion would provide a cell population comprising committed as well as uncommitted cells. Optimization of HSC expansion methods could be obtained by a combination of cytokines able to sustain renewal of pluripotent cells yet endowed with poor differentiation potential. We used variations of the combinations of cytokines described by Brugger et al. [W. Brugger, S. Heimfels, R. J. Berenson, R. Mertelsmann, and L. Kanz (1995) N. Engl. J. Med. 333, 283-287] and Piacibello et al. [W. Piacibello, F. Sanavio, L. Garetto, A. Severino, D. Bergandi, J. Ferrario, F. Fagioli, M. Berger, and M. Aglietta (1997) Blood 89, 2644-2653] to expand UCB CD34+ cells and monitored proliferation rate and phenotype after 14 days of culture. Several hematopoietic lineage-associated surface antigens were evaluated. Our data show that flt3L and thrombopoietin in combination with IL-3, while sustaining a high CD34+ proliferation rate, provide a relatively low enrichment in very early uncommitted CD34+/CD38- cells. Conversely, in the absence of IL-3, they are less effective in inducing proliferation yet significantly increase the number of CD34+/CD38- cells. A combination of the above protocols, applied simultaneously to aliquots of the same sample, would allow expansion of both committed and pluripotent HSC. This strategy may represent a significant improvement for clinical applications.

Cellular response and anti-HBs synthesis in vitro after vaccination with yeast-derived recombinant hepatitis vaccine

Two groups of subjects receiving two different doses of yeast-derived recombinant hepatitis B surface antigen (rHBsAg) (10 micrograms Gen-HB-Vax, Merck Sharp and Dohme and 20 micrograms Engerix-B, Smith Kline and French) were investigated for in vitro specific humoral and cellular response to the native protein. In vitro proliferative response was dependent on the following critical variables: (1) antigen-specific precursor lymphocytes were present in the peripheral blood for a very short time; (2) the number of circulating specific precursors was dependent on the dose of HBsAg used for vaccination; (3) the presence of antigen-presenting cells was necessary to obtain a blastogenic response in vitro. In vitro proliferation was enhanced by the addition of recombinant interleukin 2 (rIL-2). Spontaneous and stimulated (anti-CD3, pokeweed mitogen) anti-HBs antibody production in vitro was obtained in only eight out of 20 subjects after the fourth boost. Although a different immunogenicity of the two vaccines cannot be excluded, these data strongly suggest that T and B cells responsive to HBsAg present different kinetics of recirculation in the peripheral blood, depending on the antigen dose used for immunization.

A closed system for the clinical banking of umbilical cord blood

Umbilical cord blood (UCB) is a source of hematopoietic progenitor cells and is used as an alternative to the bone marrow or peripheral blood for treatment of several onco-hematological diseases. Because of the limited number of CD34+ hematopoietic stem cells present in UCB units and of the elevated costs of cryopreservation, it is of paramount importance to select the UCB units that are clinically useful before storage and optimize banking efficiency by designing reliable procedures to process and freeze the selected units. Among the different parameters characterizing UCB, nucleated cell (NC) and CD34+ cell content provides useful criteria to select UCB units since clinical data documented that the infused cell load (both NC and CD34+ cells) plays an important role in the successful outcome of transplants. By evaluating volume, CD34+ cell content, NC total amount, and NC density of 117 UCB units, we found a significant association between CD34+ cell content and NC density and total amount, indicating these parameters as useful to decide UCB clinical utility. Furthermore, we set up a fast procedure to process UCB units for storage. A system for NC separation and volume reduction of UCB samples in a dedicated, germ-free, closed circuit was developed, where plasma and red blood cells (RBC) depletion was obtained by sedimentation in the presence of a 3.5% Polygeline solution. By this separation system, both RBC depletion and high NC and CD34+ cell recoveries were achieved in 60 min, and the yield was comparable to the one obtained by other separation methods. Since Polygeline has been clinically used as a plasma expander and no toxic effects on patients were reported, the protocol can be applied in the large-scale banking of UCB.

Qualitative multiplex RT-PCR for simultaneous detection of hepatitis C virus and human immunodeficiency virus in plasma samples

This report describes the development of a one-tube multiplex reverse transcriptase (RT)-PCR assay for the simultaneous detection of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) in plasma samples. The assay was evaluated with two panels of HCV- and HIV-1-positive samples, as well as negative plasma specimens. Extraction and amplification of HCV and HIV-1 RNA from plasma samples were performed in a single reaction, and amplified genomes were detected with specific probes. Serial dilutions of the HCV and HIV-1 first World Health Organization International Standards were used to evaluate the sensitivity of the method. Two RNA controls were constructed to determine inter-assay variations and the sensitivity of the amplification step. The assay had good specificity and detected all the genotypes and subtypes tested. The analytical sensitivity of the entire assay was 100 IU/mL for HCV and 200 IU/mL for HIV-1, while the amplification step detected ten copies/reaction for HCV and 20 copies/reaction for HIV-1. The multiplex assay allowed the simultaneous extraction, amplification and detection of two virus genomes, thereby providing an important practical advantage and an efficient approach for analysing individual and pooled plasma donations.