Search PubMed⌕ Search

Biomedical subjects

C Bagnis

Publications and source records attributed to C Bagnis.

At least 37 records · Page 2Linked to original sources
PubMed1999

Expression of the nlsLacz gene in dendritic cells derived from retrovirally transduced peripheral blood CD34+ cells.

BACKGROUND AND OBJECTIVE: Gene transfer and expression of exogenous genetic information coding for an immunogenic protein in antigen presenting cells (APCs) can promote an immune response. This was investigated by retroviral transfer of a marker gene into CD34+ derived APCs. DESIGN AND METHODS: To achieve long term expression of a specific transgene in APCs, G-CSF mobilized peripheral blood CD34+ cell populations were retrovirally transduced with the bacterial nlsLacZ, a marker gene used here as a model, in the presence of IL-3, IL-6, GM-CSF and SCF prior to being induced to differentiate into dendritic and macrophage cells by GM-CSF and TNF-a. RESULTS: Addition of IL-4 was found to induce dendritic differentiation preferentially by inhibiting proliferation and differentiation of the macrophage lineage. As assessed by X-Gal staining, LacZ gene expression was observed in cells from both the dendritic lineage (CD1a+/CD14-) which still exhibits the highest immunostimulatory activity in mixed lymphocyte reaction and from the macrophage lineage (CD1a-/ CD14+). INTERPRETATION AND CONCLUSIONS: This study sets out the possibility of transducing dendritic and macrophage progenitors present in the CD34+ cell population and in using a marker gene such as nlsLacZ to study gene expression in antigen presenting cell compartments.

Antigen Presentation↗
PubMed1999

[Clinical and metabolic features of renal calculi in adults in regard to age of onset].

BACKGROUND: In this paper, the clinical and metabolic patterns of nephrolithiasis in different ages of adulthood are studied. METHODS: Eight-hundred patients observed at the Mauriziano Hospital between 1990 and 1995, were classified into 3 groups, on the basis of age at the onset of disease: A: 20 through 39 years; B: 40 through 59; C: 60 years and over. RESULTS: Calcium-oxalate stones had a lower recurrence in C (19.1%) and B (31.5%) than in A (41.7%). Pure uric acid stones recurred in 18.9% of C, 16.7% of B and 4.3% of A. The prevalence of hypercalciuria was higher in A (50.3%) than in B (35.9%) and C (36%); so did hypocitraturia. Hyperuricuria was lower in A (5%, p < 0.05) than in B (9.4%) and C (10%). Low urine pH (< 5.5) was 13% in A, 21.3% in B, 38% in C. Prevalence of hyperoxaluria was about 14% in all groups. The whole prevalence of secondary forms of stone disease was 13% in A, 12% in B and 30% in C. Differences among groups were mainly due to prevalence of urological abnormalities and urinary tract infection. In patients without metabolic disturbances. urological abnormalities or urinary tract infections altogether, were 4.6% in A; 5.2% in B; 33% in C. Urological approach removed 8% of stones in A, 5.6% in B and 10.2% in C. CONCLUSIONS: Higher morbidity in younger patients could be due to a lower prevalence of easier-passing uric acid stones. The higher occurrence of urological disturbances and struvite stones in the elderly could explain the higher morbidity in this group.

Adult↗
PubMed1998

A neutralizing anti-TGF-beta1 antibody promotes proliferation of CD34+Thy-1+ peripheral blood progenitors and increases the number of transduced progenitors.

The subset of blood cells that expresses both CD34 and Thy1 (CD90) cell surface molecules is enriched in hematopoietic stem cell activity and can be obtained from the peripheral blood of cancer patients after mobilization by chemotherapy and granulocyte colony-stimulating factor (G-CSF). Because transforming growth factor-beta1 (TGF-beta1) is a potent inhibitor of hematopoietic progenitor proliferation and differentiation, in this study we analyzed the impact of neutralizing TGF-beta1 activity during culture and retroviral transduction of CD34+Thy1+ cells. When purified CD34+Thy1+ cells were cultured in the presence of a neutralizing antibody against TGF-beta1, the percentage of cycling cells, proliferation, and absolute number of clonogenic progenitors were increased in comparison to the cultures performed without the addition of antibody. Antibody-mediated neutralization of TGF-beta1 during retroviral transduction performed by coculture of CD34+Thy1+ cells with a MFG-S-nlsLacZ retroviral vector-producing cell line did not affect the percentage of transduced progenitors as assessed by direct X-Gal staining of colonies in clonogenic assays. However, due to the better expansion of CD34+Thy1+ cells in the presence of anti-TGF-beta1, the absolute number of transduced progenitors recovered at the end of the culture was increased.

Antibodies↗
PubMed1998

[Calcium inhibitors in the management of hypertensive patients on cyclosporine].

Cyclosporine (CsA) is an immunosuppressor widely used in all postoperative transplantation protocols. Nephrotoxicity and hypertension are the major secondary effects of cyclosporine. The CsA acts on two essential regulatory mechanisms of the blood pressure: the extracellular volume and the systemic vascular resistances. The incidence of hypertension in patients treated with CsA varies from 10% to 80% in the literature. In view of two main mechanismes implicated in CsA-induced hypertension the most logical therapeutic approach would be to use diuretics and calcium inhibitors. The major drawback of diuretic therapy is the risk of hyperuricaemia and attacks of gout, the predisposition to which is already increase by treatment with CsA. In addition, renal failure may rarely be observed. The calcium channel blockers are the drugs of choice in the treatment of CsA-induced hypertension. Not only are they effective in decreasing the blood pressure, but they also have a major advantage of having a nephroprotective effect against CsA. Cyclosporine is metabolised in the liver by cytochrome P450 3A4 dependant enzymes. Many pharmacological interferences have been described with this drug and other pharmacological agents. This type of interaction has been described with certain calcium inhibitors which inhibit hepatic and digestive degradation of cyclosporine and therefore increase its plasma concentrations. The choice of calcium inhibitors should be based on criteria of efficacy and tolerance and on the drug's pharmacokinetics. The interaction between cyclosporine and some calcium inhibitors exposes the patients to the risk of overdosage when treatments is instituted and of underdosage when the treatment is withdrawn.

Blood Pressure↗
PubMed1997

Successful reconstitution of human hematopoiesis in the SCID-hu mouse by genetically modified, highly enriched progenitors isolated from fetal liver.

Highly purified CD34++CD38-Lin- hematopoietic progenitors isolated from human fetal liver were infected with the murine retroviral vector, MFG nls-LacZ, which encodes a modified version of the Escherichia coli beta-galactosidase gene. Progenitors that were cocultured with the packaging cell line could reconstitute human bone marrow or thymus implanted in SCID-hu mice. Expression of the beta-galactosidase gene was observed in primitive and committed clonogenic progenitors, mature myeloid, B-lineage cells, and T-lineage cells for up to 4 months after injection into SCID-hu mice. Furthermore, hematopoietic reconstitution by genetically modified progenitor cells could be achieved by the injection of the cells generated from as few as 500 CD34++CD38-Lin- cells, suggesting efficient retroviral gene transfer into fetal liver progenitors.

Animals↗
PubMed1997

Retroviral transfer of herpes simplex virus-thymidine kinase and beta-galactosidase genes into U937 cells with bicistronic vector.

In this study we describe a new retroviral vector utilizing an internal ribosome entry site (IRES) from encephalomyocarditis virus to co-express two genes. One is the herpes simplex virus type 1 thymidine kinase gene (HSV-TK) which induces sensitivity to ganciclovir, and the second is the bacterial beta-galactosidase gene (LacZ) which was revealed by an histochemical staining with 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). We engineered the U937 human cell line to co-express both genes and monitored transduced cells using X-Gal staining. Several transduced clones were selected. The clones exhibiting X-Gal positive cells were sensitive to ganciclovir treatment (1 microgram/ml) while X-Gal negative clones were not. Monoclonal cell lines showed a single copy of the provirus integrated in their genome with the TK-IRES-LacZ sequence stably inserted in all clones. The band distribution pattern of the proviral DNA differed only at the long terminal repeat (LTR) level. Northern blot analysis of an X-Gal positive/ganciclovir sensitive clone showed an mRNA band of 6 kb with both LacZ and TK probes. An X-Gal negative/ganciclovir resistant clone was negative with both probes. This report shows: (1) a therapeutic gene can be linked to a marker gene by an IRES element achieving equivalent expression of both proteins; (2) the co-expression of a marker gene makes fluorescein-di-beta-D-galactopyranoside staining possible, and consequently separation of cells expressing the LacZ gene by fluorescence activated cell sorting. Thus the cells expressing the HSV-Tk gene are enriched; (3) the use of a marker gene such as LacZ could open up interesting perspectives in gene therapy protocols because of the opportunity to monitor the transduced cells using a simple cytochemical stain.

Cloning, Molecular↗
PubMed1997

Role of endothelium-derived nitric oxide-endothelin balance in contrast medium-induced acute renal vasoconstriction in dogs.

RATIONALE AND OBJECTIVES: The authors evaluated the involvement of nitric oxide and endothelin in radiographic contrast medium-induced changes in renal hemodynamics. METHODS: Eleven anesthetized healthy dogs were each studied during three periods. Thirty minutes before the first, second, and third periods, the dogs received 1 mL per kilogram of body weight of isotonic saline, L-N-nitro-L-arginine-methyl-ester (L-Name, 10 mg/kg intravenously), and L-arginine (500 mg/ kg intravenously), respectively. Renal blood flow (RBF) and mean arterial blood pressure were continuously monitored. The glomerular filtration rate (GFR) was evaluated by means of polyfructosan clearance. RESULTS: Contrast medium induced a significant (P < .05) decrease in RBF and GFR and a significant (P < .05) increase in urinary endothelin excretion. L-Name enhanced the effect of contrast media on RBF and GFR. L-arginine attenuated the effect of L-Name on the contrast medium-induced reduction of GFR. CONCLUSION: These findings support the hypothesis that acute contrast medium-induced intrarenal vasoconstriction may involve an imbalance of endothelial vasoactive agents, nitric oxide, and endothelin, and they confirm the involvement of hemodynamic changes in contrast medium-induced nephropathy.

Animals↗
PubMed1997

Cre/loxP-mediated excision of a neomycin resistance expression unit from an integrated retroviral vector increases long terminal repeat-driven transcription in human hematopoietic cells.

Recombinant retroviruses are currently the most attractive vehicles for gene transfer into hematopoietic cells. Retroviral vectors often contain an easily selectable marker gene in addition to the gene of interest. However, the presence and selection for expression of the selectable gene often result in a significant reduction of the expression of the gene of interest in the transduced cells. In order to circumvent this problem, we have developed a Cre/loxP recombination system for specific excision of the selectable expression unit from integrated retroviruses. A retroviral vector, containing both a neomycin resistance expression unit flanked by loxP sites and granulocyte-macrophage colony-stimulating factor cDNA, was used to transduce the human hematopoietic K-562 cell line. Four transduced cell clones were then superinfected with a retrovirus containing a Cre recombinase expression unit. Molecular analyses of 30 doubly transduced subclones showed a strict correlation between cre expression and loxP-flanked selectable cassette excision, thus implying that Cre recombinase activity is very efficient in a retroviral context. Moreover, the excision of the selectable cassette results in a significant increase of granulocyte-macrophage colony-stimulating factor transcription driven by the retroviral promoter.

Animals↗
PubMed1997

Comparative acute nephrotoxicity of FK-506 and ciclosporin in an isolated in situ autoperfused rat kidney model.

The acute hemodynamic effects of ciclosporin A (Cs-A; 40 and 20 mg/kg), FK506 (1.5 and 0.4 mg/kg), and their vehicles were studied in an in situ autoperfused rat kidney model. Cs-A (60 +/- 7 and 66 +/- 5% of the initial value, respectively; p < 0.05 vs. control group) and FK506 (89 +/- 3 and 77 +/- 3% of the initial value respectively; p < 0.05 vs. control group) induced a significant fall in renal blood flow. Cs-A significantly increased the renal vascular resistance, whereas FK506 had no effect. The glomerular filtration rate (inulin clearance) declined significantly in all groups. Cremophore and FK506 vehicle had no hemodynamic effect on the glomerular filtration rate. In our model, FK506 had less vasoactive effects on the renal hemodynamics than Cs-A.

Animals↗
PubMed1997

Stem Cell-Based Gene Therapy.

Many researchers and clinicians wonder if gene therapy remains a way to treat genetic or acquired life-threatening diseases. For the last few years, many experimental, pre-clinical, and clinical data have been published showing that it is possible to transfer with relatively high efficiency new genetic information (transgene) in many cells or tissues including both hematopoietic progenitor cells and differentiated cells. Based on experimental works, addition of the normal gene to cells with deletions, mutations, or alterations of the corresponding endogenous one has been shown to reverse the phenotype and to restore (in some case) the functional defect. In spite of very attractive preliminary results, however, suggesting the feasibility and safety of this process, therapeutically efficient gene transfer and expression in targeted cells or tissues must be proven. In this review, we will focus primarily on the attempts to use gene transfer in hematopoietic stem cells as a model for more general genetic manipulations of stem cells. Hematopoietic stem cells are included in a subset of bone marrow, cord blood, or peripheral blood cells identified by the expression of the CD34 antigen on their membrane.

Journal Article↗
PubMed1997

No need to adjust the dose of 311C90 (zolmitriptan), a novel anti-migraine treatment, in patients with renal failure not requiring dialysis.

311C90 ("Zomig", zolmitriptan), is a novel and selective, centrally and peripherally acting 5 HT1B/1D receptor agonist in development for the acute, oral treatment of migraine. We have conducted a parallel group study in patients with moderate/severe renal impairment (creatinine clearance < or = 40 ml/min) and age- and sex-matched healthy volunteers (creatinine clearance > or = 60 ml/min). All subjects received a single, 10 mg dose of 311C90. Mean peak concentrations of 311C90 and its pharmacologically active N-desmethyl metabolite (183C91) were similar in both groups although AUC0-infinity for 183C91 was increased by 35% in the renally impaired patients. Other pharmacokinetic parameters were little changed apart from the expected reduction in CLR and urinary recovery and a small increase of 0.9 and 1.0 h, respectively, in the mean half-lives of 311C90 and 183C91. For the 2 inactive metabolites, the N-oxide (1652W92) and the indolacetic acid (2161W92), mean peak concentrations were approximately 3 times higher in renally impaired patients than in healthy volunteers and AUC0-infinity was 6-7.5 times higher. CLR for these metabolites was approximately 90% lower in renal impairment and half-life of both was increased approximately 3-fold. Baseline blood pressures were higher in the renally impaired group. After 311C90 there was a transient, small increase in blood pressure in both groups. There was little difference in the increase in diastolic blood pressure between the groups (16 mmHg in both) but the rise in systolic blood pressure was greater in the renally impaired group (23 mmHg vs 16 mmHg in healthy subjects). The lack of substantial changes in the plasma concentrations of both parent compound and 183C91, and the similarity of the changes in blood pressure, in renally impaired subjects compared to healthy volunteers suggest that there is no reason to adjust the dose of 311C90 in patients with renal impairment.

Adult↗
PubMed1996

Prevention of cyclosporin nephrotoxicity with a platelet-activating factor (PAF) antagonist.

BACKGROUND: Cyclosporin (CsA) is a potent immunosuppressive drug whose main side-effect is nephrotoxicity. In the kidney, CsA induces vasoconstriction with a decrease in renal blood flow (RBF) and glomerular filtration rate (GFR) and a significant increase in renal vascular resistance (RVR). CsA enhances platelet-activating factor (PAF) synthesis in mesangial cells in vitro. PAF, a secondary mediator of anaphylaxis and inflammation, exhibits vasoactive properties in the kidney similar to those of CsA. METHODS: The in situ autoperfused rat kidney model was used to investigate whether PAF plays a role in the haemodynamic injury induced by CsA. RESULTS: In this model, CsA (40 mg/kg and 20 mg/kg i.v.) induced a significant decrease in RBF and in GFR and an increase in RVR. BN 52021, a potent and specific PAF antagonist (20 mg/kg i.v. bolus dose) induced a significant increase in GFR (137 +/- 32% of initial value, P < 0.05). BN 52021 (20 and 10 mg/kg) also significantly prevented the decline in RBF and GFR induced by CsA. CONCLUSIONS: We have demonstrated that the PAF antagonist BN 52021 can minimize the alteration of renal function induced by CsA.

Animals↗
PubMed1995

Hematological reconstitution and gene therapy: retroviral transfer of the bacterial beta-galactosidase activity into human hematopoietic CD34+ cell populations and into T lymphocytes derived from the peripheral blood.

We report the possibility to transfer marker genes coding for beta-galactosidase activity using retroviral vectors into human peripheral blood CD34+ cells, peripheral blood T-lymphocytes and into the growth factor-dependent human hematopoietic cell line TF-1. Using the MFG-nisLacZ and the FLac vector and various packaging cell lines, we demonstrated retroviral transfer and high expression of a bacterial beta-galactosidase activity induced by the nisLacZ gene or the Sh-ble/LacZ gene. Kinetics of expression of the transgenes were analyzed both in primary cells and cell lines. Absence of cytotoxicity related to the expression of the bacterial beta-galactosidase was assessed in both cell types. These results open interesting prospectives for the use of the beta-galactosidase activity to mark and follow the fate of genetically modified cells isolated from patients prior to reimplantation.

Antigens, CD↗
PubMed1994

Retroviral transfer of the nlsLacZ gene into human CD34+ cell populations and into TF-1 cells: future prospects in gene therapy.

Few data are available concerning behavior of reimplanted human hematopoietic cells after autologous stem cell transplantation. This paper reports the possibility to transfer gene markers coding for beta-galactosidase (beta-Gal) activity by retroviral vectors into a human leukemic growth factor-dependent cell line, TF-1, and into human hematopoietic progenitors isolated from peripheral blood or bone marrow. Using various combinations of retroviral vectors and packaging cell lines, we demonstrated high expression of a bacterial beta-Gal activity induced by the LacZ gene, the nlsLacZ gene, or the Sh-ble/LacZ gene, in human hematopoietic cells. The expression of the nlsLacZ construct was stable until the end of the culture in infected CD34+ cell-enriched cell populations, and a slow decrease of transgene expression was observed in a transduced TF-1 cell population during a 1-year long-term culture. Data obtained with the nlsLacZ gene demonstrate that both retroviral transfer and corresponding gene expression were not found to modify the pattern of cell proliferation and differentiation. These results open interesting prospectives for the use of the nlsLacZ gene to mark and follow the fate of progenitor cells isolated from patients with cancers prior to reimplantation.

Animals↗