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D Valerio

Publications and source records attributed to D Valerio.

At least 55 records · Page 3Linked to original sources
PubMed1997

Development of safe and efficient retroviral vectors for Gaucher disease.

We have generated amphotropic and Gibbon ape leukemia (GaLV) viruses carrying either a full-length (IG-GC2) or a shortened glucocerebrosidase cDNA (IG-GC4). For all recombinant retroviruses, a single infection was sufficient to augment glucocerebrosidase activity in unselected Gaucher type I and type II fibroblasts to levels which can be considered therapeutic. Transfer efficiency of the glucocerebrosidase cDNA into normal human and Gaucher type I CD34+ cells, using supernatant transduction, ranged from 4 to 50% as established on vector-positive CFU-GM. In these experiments, GaLV and amphotropic virus were equally efficient in transducing early human progenitors. Importantly, mixing amphotropic and GaLV pseudotyped retroviruses resulted in significantly higher transduction efficiencies as compared with single infections, up to 70% vector-positive CFU-GM. Glucocerebrosidase activity, measured in the progeny of human CD34+ cells, increased up to 460% compared with mock-infected CD34+ cells. Upon transduction of Gaucher CD34+ bone marrow cells the glucocerebrosidase deficiency was reversed.

Antigens, CD34↗
PubMed1997

Isolation of fetal erythroid cells from maternal blood based on expression of erythropoietin receptors.

Fetal nucleated red cells which pass into the maternal circulation during pregnancy are a potential cell source for non-invasive prenatal genetic diagnosis. To sort these rare cells with a high degree of specificity, we focussed our attention on the erythropoietin receptor, a strictly erythroid-specific antigen. We first labelled these receptors with biotin-(sialyl)-erythropoietin, then isolated the erythroid cells by magnetic beads conjugated with streptavidin in a MiniMACS (magnetic cell separator). The effectiveness of this strategy for the enrichment of fetal cells was evaluated by assessing its accuracy for gender prediction in 18 male-bearing pregnancies. Polymerase chain reaction (PCR) results on maternal blood samples sorted for Epo-r and CD71 antigens displayed similar sensitivity (55% Epo-r, 61% CD71) in detecting Y-specific sequences while immunocytochemical studies on four maternal blood samples, sorted after increasing the binding time of the ligand to Epo-r (8 h), showed a substantial improvement in fetal cell recovery and purity. We conclude that sorting by Epo-r/biotin-(sialyl)-erythropoietin provides effective enrichment of fetal nucleated red cells allowing the possibility of direct prenatal cytogenetic analysis by multiprobe fluorescent in-situ hybridization (FISH).

Antigens, CD↗
PubMed1997

Preclinical testing of recombinant adenoviral herpes simplex virus-thymidine kinase gene therapy for central nervous system malignancies.

OBJECTIVES: Adenoviral gene transfer and killing efficiency using the thymidine kinase (TK)/ganciclovir (GCV) mechanism was evaluated in human cancer cells occurring as central nervous system tumors. The effectiveness of this approach was tested in vitro and in experimental models for brain tumor and leptomeningeal metastases in rats in vivo. Recombinant adenoviruses with different promoters were compared. METHODS: Adenoviral vectors harboring a marker (lacZ) or a TK gene were constructed. Transcription of genes was under the control of either the adenovirus Type 2 major late promoter (MLP) or the human cytomegalovirus (CMV) immediate early gene promoter. lacZ expression and GCV killing efficiency after TK gene transfer in several human tumor cells was evaluated in vitro. The 9L rat brain tumor and leptomeningeal metastases models were used to determine the effectiveness of adeno-TK and subsequent GCV treatment in vivo. MLP and CMV containing adenoviral vectors were compared. RESULTS: Gene expression and the killing of tumor cells were very efficient in all human tumor cell lines tested. The adenovirus containing the CMV promoter showed cytopathic effects in cultured tumor cells at high multiplicity of infections but also greater cell killing efficiency after TK/GCV treatment, as compared to the MLP promoter. Although both the MLP and CMV vectors showed a significant dose-dependent therapeutic effect, animals treated with recombinant adenovirus containing the CMV promoter showed significantly longer survival time (brain tumors) or symptom-free periods (leptomeningeal metastases). CONCLUSION: This study demonstrates the therapeutic efficiency and feasibility of the TK/GCV approach in experimental brain tumors and leptomeningeal metastases. It also demonstrates that the promoter driving the transgene in an adenoviral vector influences toxicity and efficiency of treatment.

Adenoviridae↗
PubMed1996

Gene transfer into hematopoietic stem cells of nonhuman primates.

Nonhuman primates provide an appropriate preclinical large-animal model to test the efficacy of bone marrow gene therapy procedures. Successful retroviral vector-mediated gene transfer into monkey pluripotent hematopoietic stem cells (PHSC) has closed the gap between gene transfer experiments in mouse models and clinical application of bone marrow gene therapy. After initial bone marrow transplant failures, ex vivo bone marrow culture conditions were found that sufficiently supported maintenance of the long-term repopulating ability of genetically modified autologous monkey grafts. The efficiency of gene transfer into primate PHSC has, however, remained at least one order of magnitude lower than has been achieved in mice. Similar gene transfer efficiencies have been obtained with total bone marrow grafts, CD34+ bone marrow grafts, and mobilized peripheral blood progenitor cell grafts; however, various attempts to increase the transduction efficiency have been without significant success. Primate PHSC seem to require quite different culture conditions for their maintenance and transduction than mouse PHSC, in particular regarding hematopoietic growth factor addition. In contrast to observations in other species, some form of conditioning appeared essential for engraftment of transduced PHSC in monkeys. Although it has been shown that mouse retroviruses can replicate in monkeys and are capable of inducing neoplasms, experiments in monkeys have sufficiently confirmed the safety of current gene transfer procedures to allow their clinical application.

Animals↗
PubMed1996

Single chain Ig/gamma gene-redirected human T lymphocytes produce cytokines, specifically lyse tumor cells, and recycle lytic capacity.

To enable construction of CTL with known predefined Ab specificity for adoptive immunotherapy, we constructed a chimeric scFv/gamma gene composed of the variable regions of a mAb joined to the Fc(epsilon)RI signaling receptor gamma-chain of mast cells. Introduction of this chimeric receptor into CTL rendered these lymphocytes specific for renal cell carcinoma. This approach combines the specificity of tumor-selective Abs with the efficacy of CTL to destroy tumor cells. We not only demonstrated that the transduced CTL functionally express the scFv/gamma receptor for a prolonged period of time (4.5 mo of in vitro culture), but also showed high levels of Ab-dictated lysis of renal cell carcinoma similar to that of normal CTL, and importantly, we demonstrated that these CTL can recycle their lytic activity. Moreover, these scFv/gamma-expressing T lymphocytes produce cytokines upon stimulation with the relevant target cell. These results together with the donor independence of our gene transduction protocol demonstrate the feasibility of redirecting T lymphocytes for cancer treatment.

Base Sequence↗
PubMed1996

Frequency analysis of multidrug resistance-1 gene transfer into human primitive hematopoietic progenitor cells using the cobblestone area-forming cell assay and detection of vector-mediated P-glycoprotein expression by rhodamine-123.

Transfer of the multidrug resistance-1 (MDR1) gene into hematopoietic progenitor cells may reduce myelotoxicity of MDR1-related cytotoxic agents and therefore allow dose intensification. Mobilized peripheral blood progenitor cells (PBPC) can be obtained in ample quantity and are a suitable target cell population. CD34-selected PBPC samples (n = 6) were transduced with cell-free supernatant (SNT) of a cell line producing recombinant retrovirus containing the human MDR1 gene. Limiting-dilution long-term cultures were employed that allow continuous monitoring of stroma-adherent cobblestone areas (CA) and comparison of their frequency in a 5-log range over time. MDR1 provirus integration in CA-containing wells followed single-hit kinetics. According to Poisson statistics, proviral DNA was contained in 22% of unselected cobblestone area-forming cells (CAFC) at week 6, which represent primitive hematopoietic precursors. In comparison, 1.0 +/- 0.44% (mean +/- SEM) of week-6 CAFC were expressing P-glycoprotein at sufficient levels to convey vincristine resistance, suggesting low expression of the retroviral vector or splicing of the vector-drived mRNA in hematopoietic progenitor cells. Next we analyzed lineage-committed progenitors. The proviral DNA was detectable in 20-66% of colony-forming units granulocyte-macrophage (CFU-GM) while corresponding percentages (25-52%) of CD34+ PBPC were in the S/G2M phase of the cell cycle at the end of the transduction period. The proportion of vincristine-resistant CFU-GM was similar to the CAFC data and no significant differences were found between various MDR1-SNT transduction schedules whereas MDR1 co-cultivation, which served as a positive control, yielded significantly higher proportions of resistant colonies (5.3 +/- 1.4%, IL-3, 96 hr, p < or = 0.05). Assessment of rhodamine-123 (Rh-123) efflux in the myelo-monocytic progeny of MDR1-transduced cells mirrored the colony assay results in the SNT and co-cultivation groups. Less culture effort was required in the Rh-123 assay and functional characterization of the transferred P-glycoprotein was possible using cyclosporin A. Further development toward an effective MDR1 gene therapy should be facilitated by the CAFC assay, which allows estimation of the retroviral gene transfer frequency into primitive hematopoietic cells, and by the Rh-123 assay, which permits tractable side-by-side assessments of numerous MDR1 transduction protocols or different MDR1-SNT lots.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

In vitro and in vivo gene transfer to pulmonary cells mediated by cationic liposomes.

Cationic liposomes have been proposed as alternative to adenovirus in the treatment of cystic fibrosis lung disease. Therefore, we have investigated the efficiency of two lipid mixtures in mediating gene transfer in in vitro and in vivo models. The cationic lipid DOTMA (N-(1-(2,3(dioleyloxy)propyl)-n,n,n-trimethylammoniumchloride++ +) and DOGS (dioctadecylamidoglycylspermine) were used in combination with the neutral lipid DOPE (dioleoylphosphatidylethanolamine). The relative transfection efficiencies of the two cationic liposomes were tested using the bacterial beta-galactosidase (lacZ) and the firefly luciferase genes. Gene expression was detected in both cell limes and primary culture of rhesus monkey airway epithelium after transfection with plasmid DNA complexed with DOGS/DOPE or DOTMA/DOPE. Transfection efficiency of both types of lipids was higher in the mouse fibroblast 3T3 cell line as compared to human carcinoma A549 cells and primary epithelial cultures. Administration of DNA-liposome complexes via intratracheal instillation resulted in expression of the lacZ and luciferase marker gene in the mouse airways. In vivo transfection mediated by both types of liposomes were proven to be far less efficient than adenovirus treatment.

3T3 Cells↗
PubMed1996

Herpes simplex virus thymidine kinase gene therapy for rat malignant brain tumors.

Transfer of a herpes simplex virus-derived thymidine kinase (HSV-tk) gene into brain tumor cells and subsequent ganciclovir (GCV) treatment has been shown by others to be an effective treatment in rats with intracerebrally inoculated 9L gliosarcomas. Mechanism of action and reproducibility are, however, still a matter of debate. We have used the same model to test the therapeutic effects of both retrovirus- and adenovirus-mediated transfer of the HSV-tk gene followed by GCV treatment. Survival time of rats with intracerebral 9L tumors was significantly prolonged after a single administration of adenovirus carrying a HSV-tk gene as compared to controls. Retrovirus-mediated gene transfer also resulted in significantly prolonged survival time when recombinant retrovirus-producing cells were transplanted. Direct injection of the recombinant retrovirus, HSV-tk-expressing cells, virus-producing cells without GCV administration and recombinant retrovirus-lacZ or interleukin-2 (IL-2)-producing cells did not result in tumor cell kill. In the present study, no significant difference in survival of 9L brain tumor carrying rats was found after treatment with adenovirus as compared to retrovirus-mediated HSV-tk-mediated gene transfer and subsequent GCV treatment.

Adenoviruses, Human↗
PubMed1996

Culture of fetal erythroid progenitor cells from maternal blood for non-invasive prenatal genetic diagnosis.

Fetal committed erythroid progenitors CFU-E and M-BFU-E released into the maternal circulation during pregnancy are ideal candidates for in vitro proliferation since their lifespan is short and they can form colonies of 100-1000 cells in a semi-solid medium. In order to propagate these cells with a high rate of purity, a strategy was devised based on their prior enrichment with biotin-labelled human erythropoietin ligand and magnetic sorting before culturing in a suitable medium. Eight euploid pregnancies investigated in order to address this issue produced fetal clones in cultures with 18 per cent purity as assessed by polymerase chain reaction (PCR) analysis for Y-specific sequences, immunocytochemical staining for fetal gamma-globin, and fluorescence in situ hybridization (FISH) study. The CFU-E-type colony was the most represented progenitor, followed by M-BFU-E, and only occasionally was the detection of CFU-GEMM recorded. The retrospective diagnosis of two cases of fetal Down's syndrome by culturing fetal cells from maternal blood was accomplished for the first time. FISH analysis disclosed a strong presence of fetal trisomic cells (70 per cent and 40 per cent in the two cases). This strong presence would suggest a preferential leakage into maternal blood. The overall results of this study demonstrate that fetal cells can be cultured in vitro with reliable reproducibility, thus making the prospect of a non-invasive prenatal genetic diagnosis realistic.

Cells, Cultured↗
PubMed1996

Full genetic rescue of adenosine deaminase-deficient mice through introduction of the human gene.

We have shown recently that adenosine deaminase (ADA)-deficient mice die perinatally with severe liver cell degeneration. In addition to enzyme substitution, we report the restoration of viability through introduction of the human ADA gene. The ADA gene is subject to complex developmental and tissue-specific regulation. To include the cis-regulatory elements necessary for correct regulation of the human ADA gene, a large transgenic locus constituting the human ADA gene with 10 kb of 5' and 4 kb of 3' flanking sequences was generated by co-injection of two overlapping DNA fragments into murine zygotes. Probably as a result of extrachromosomal (homologous) recombination between the fragments, one of the two transgenic lines contained a reconstituted, functional human ADA gene. As in man, human ADA expression generally was low in these transgenic mice, but high in the thymus, spleen and gastro-duodenal part of the gut. Apparently, all cis-regulatory elements essential for a human expression pattern were incorporated in the transgene and were functional in the murine background. Similarly to man, the upper alimentary tract of the transgenic mice revealed low human ADA activity in contrast to extremely high levels of murine ADA. The human gene probably lacks the cis-regulatory elements that target high level murine ADA expression to the murine upper alimentary tract. ADA-deficient mice rescued by introduction of the human ADA transgene appeared histologically and immunologically normal. Apparently, human ADA can complement murine ADA in all tissues, even in the epithelium of the upper alimentary tract where human ADA activity is as much as 70-fold lower than murine ADA activity in wild-type mice. Clearly, the lethal phenotype of ADA-deficient mice is due to the absence of ADA.

Adenosine Deaminase↗
PubMed1996

Treatment of leptomeningeal metastases in a rat model using a recombinant adenovirus containing the HSV-tk gene.

The authors constructed recombinant adenoviral vectors to investigate their potential for gene therapy treatment of leptomeningeal metastases. Several human cell lines that were derived from tumors occurring as leptomeningeal metastases and that were infected in vitro with major late promoter recombinant adenovirus containing the luciferase (luc) gene (IG.Ad.MLP.luc) showed high levels of expression. When these human tumor cell lines were infected in vitro with recombinant adenovirus harboring the herpes simplex virus-thymidine kinase (HSV-tk) gene (IG.Ad.MLP.TK), they were highly sensitive to the killing effects of ganciclovir (GCV). Transduction efficiency of leptomeningeal tumor cells in vivo was assessed by injecting 9-L rat brain tumor cells into the cerebrospinal fluid of Fischer rats via the cisterna magna. After 3 days, recombinant adenovirus containing the lacZ reporter gene (IG.Ad.MLP.lacZ) was injected via the same route. Six days after tumor cell injection, expression of the reporter gene was observed in tumor cells along the total neural axis. Subsequently, rats with leptomeningeal metastases were treated 3 days after tumor cell injection with HSV-tk. Beginning on the next day, GCV was injected intraperitoneally for 10 days. The rats that developed neurological symptoms were killed immediately. The symptom-free latency of every rat was determined. The rats treated with HSV-tk and subsequent GCV had significantly longer (p < 0.01) symptom-free latency than all control groups. This study demonstrates the feasibility and efficacy of this therapeutic approach in a rat model. Clinically, it should be used in the palliative treatment of patients with leptomeningeal metastases.

Adenoviridae↗
PubMed1996

Cell cycle state, response to hemopoietic growth factors and retroviral vector-mediated transduction of human hemopoietic stem cells.

A multi-parameter fluorometric analysis was applied to study in vitro proliferation and expansion of a candidate hemopoietic stem cell population, ie CD34brightLin cells. In primary hemopoietic cell samples the CD34brightLin population comprised on average, 1% of CD34+ cells from bone marrow (BM) or umbilical cord blood and 0.1% of mobilized peripheral blood CD34+ cells. The fraction of CD34brightLin cells engaged in the S+G2/M phases of the cell cycle was largest in regenerating BM (10.6% versus 1-2% in the other sources). Maintenance of CD34+ BM cells in hemopoietic growth factor supplemented liquid cultures resulted in a decrease of the CD34brightLin population in most samples. Cell cycle analysis showed the constant existence of proliferating CD34+ cells during the culture period. The fraction of cycling CD34brightLin cells was, however, very small and only occasionally exceeded input values. At all tested time-points during culture, BM CD34+ cells could be transduced by a single incubation with a recombinant retrovirus supernatant. CD34brightLin cells, however, were much more refractory to retroviral vector-mediated transduction. This could be explained only in part by quiescence of CD34brightLin cells. Hence, factors other than cell proliferation clearly influence the early stages of retroviral transduction of human hemopoietic stem cells.

Antigens, CD34↗
PubMed1996

Maternal serum screening of fetal chromosomal abnormalities by AFP, UE3, hCG and free-beta hCG. Prospective and retrospective results.

We have conducted a prospective study to ascertain the reliability of the triple test in detecting aneuploid fetuses in a Mediterranean, pregnant population. 2978 singleton pregnancies in the 15-22 completed week's gestational range were enrolled in this study between January 1992 and June 1994. The measurements of the analytes AFP, hCG and UE3 in the maternal serum combined with maternal age in a multivariate risk approach were utilized to detect pregnancies at increased risk (cut of > or = 1:270) to undergo prenatal diagnosis by amniocentesis. This screening was preferentially reserved to young patients (median age of the population 29 years). 212 pregnancies resulted screen positive to triple test and 178 accepted fetal chromosomal analysis. Three Down's syndrome, a Turner 45XO and a triploidy 69XXY were detected in the sample undergoing prenatal diagnosis. One aneuploid pregnancy (Down's syndrome) was recorded in the population with negative result (risk < 1:270). As part of this study we have subsequently compared the sensitivity of the test substituting total hCG with free-beta marker in samples from aneuploid pregnancies (16 cases) and unaffected pregnancies (300 cases). The detection rate for the two combinations was identical (81%) as well as the false positive rate (5.7% versus 5.3%) derived from the normal samples. All together these combined results of our study support the increasing call for triple test in screening programmes and indicate that further data be collected before recommending the replacement of total hCG with free-beta analyte.

Adult↗
PubMed1996

Bone marrow gene transfer in three patients with adenosine deaminase deficiency.

Adenosine deaminase (ADA) deficiency results in severe combined immune deficiency disease (SCID), which is fatal without treatment. Allogeneic bone marrow transplantation (BMT) is the treatment of choice if an HLA-identical sibling bone marrow donor is available, resulting in almost 100% cure rate. BMT-related mortality is high in patients lacking such a donor. For these patients, efficient transfer of a recombinant ADA gene into hematopoietic stem cells is a therapeutic option if it results in the outgrowth of a 'genetically repaired' lymphoid system. Based on successful gene transfer studies in monkeys, we performed retrovirus-mediated gene transfer into CD34+ bone marrow cells of three patients with ADA deficiency. Two patients received bovine ADA conjugated to polyethylene glycol (PEG-ADA); in the third patient, PEG-ADA was started 4 months after gene transfer. Gene transfer resulted in a 5-12% transduction frequency of in vitro colony forming cells (CFU-Cs). No toxicity was observed during and after infusion of the graft. Following infusion of the transduced CD34+ cells, transduced granulocytes and mononuclear cells persisted in the circulation for 3 months. In addition, the gene was present in the marrow of one of the patients at 6 months after gene transfer. Expression of the gene was not detected. After this period, the gene could not be detected. In monkey studies we showed that myeloablation, which was not performed in the patients, may enhance engraftment of genetically modified cells. We hypothesize that lack of myeloablation, administration of bovine ADA and low numbers of transduced progenitor cells all may have contributed to the relative low numbers of transduced cells in the patients. Under these conditions, no selective advantage of the genetically corrected progenitor cells was observed.

Adenosine Deaminase↗
PubMed1996

[Cytogenic characterization of chromosome markers detected at amniocentesis: implications for karyotype-phenotype correlations].

The detection of marker chromosomes at prenatal diagnosis raises serious concerns regarding the phenotypic consequences on the fetus. Traditionally the classical approach to the problem relied upon the cytogenetic analysis of the marker chromosome by different banding techniques to ascertain its euchromatic content. This indirect methodology doesn't allow to trace the origin of the marker and to properly narrow the molecular boundaries of the euchromatic region. FISH technology by means of DNA probes regionally localized is a powerful tool to address these issues, allowing to determine the exact origin of the markers and more refined criteria for studying karyotype-phenotype correlations. This facilitates genetic counseling and the decision making for the parents. Here we describe our experience of integrated approach (molecular and classical cytogenetics) in two de novo cases of marker chromosomes (iso 18p and inv dup 15), detected at amniocentesis.

Adult↗
PubMed1995

Retroviral transfer of the multidrug resistance-1 gene into lineage-committed and primitive hemopoietic cells.

Transfer of the multidrug resistance-1 (MDR1) gene to hemopoietic cells for myeloprotection against cytostatic agents is a new and rapidly developing field in "cancer gene therapy." Before clinical application, safety and efficacy criteria need to be met. The retroviral producer cell lines and the retroviral supernatant need to be tested for replication-competent retrovirus and contamination with adventitious agents. The cell source needs to contain sufficient hemopoietic cells with repopulating ability. We used CD34(+)-selected mobilized peripheral blood progenitor cells (PBPC) for MDR1 transductions in order to obtain a favorable vector to target cell ratio. An analysis of 249 patients who had undergone PBPC harvesting revealed that primarily solid tumor and non-Hodgkin's lymphoma patients are eligible for CD34+ selection. They can be expected to retain sufficient CD34+ cells for rapid and sustained engraftment after myeloablative therapy if the CD34+ cell loss (approximately 50%) during the procedure is taken into account. Clinical MDR1 gene therapy protocols focus on these two patient groups. Next we characterized MDR1 gene transfer into lineage-committed and primitive hemopoietic cells. Provirus-specific polymerase chain reactions showed a high efficiency gene transfer into colony-forming-units granulocyte-macrophage and long-term culture cells. The level of the conferred P-glycoprotein expression was estimated by fluorescence-activated cell sorting analysis to be up to 3 log above mock-transduced controls. The cobblestone area forming cell assay, which is a stroma-dependent long-term culture assay measuring frequencies of stem cell subsets in a limiting-dilution set-up, allowed demonstration of sustained expression of the MDR1 gene in the progeny of primitive hemopoietic cells. This is a favorable basis for a clinical MDR1 gene therapy trial.

Drug Resistance, Multiple↗
PubMed1995

Adenosine-deaminase-deficient mice die perinatally and exhibit liver-cell degeneration, atelectasis and small intestinal cell death.

We report the generation and characterization of mice lacking adenosine deaminase (ADA). In humans, absence of ADA causes severe combined immunodeficiency. In contrast, ADA-deficient mice die perinatally with marked liver-cell degeneration, but lack abnormalities in the thymus. The ADA substrates, adenosine and deoxyadenosine, are increased in ADA-deficient mice. Adenine deoxyribonucleotides are only modestly elevated, whereas S-adenosylhomocysteine hydrolase activity is reduced more than 85%. Consequently, the ratio of S-adenosylhomocysteine (AdoMet) to S-adenosyl homocysteine (AdoHcy) is reduced threefold in liver. We conclude that ADA plays a more critical role in murine than human fetal development. The murine liver pathology may be due to AdoHcy-mediated inhibition of AdoMet-dependent transmethylation reactions.

Adenosine Deaminase↗