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N C Zoumbos

Publications and source records attributed to N C Zoumbos.

At least 19 recordsLinked to original sources
PubMed2006

Gene transfer into human hematopoietic progenitor cells with an episomal vector carrying an S/MAR element.

Episomally maintained self-replicating systems present attractive alternative vehicles for gene therapy applications. Recent insights into the ability of chromosomal scaffold/matrix attachment regions (S/MARs) to mediate episomal maintenance of genetic elements allowed the development of a small circular episomal vector that functions independently of virally encoded proteins. In this study, we investigated the potential of this vector, pEPI-eGFP, to mediate gene transfer in hematopoietic progenitor cell lines and primary human cells. pEPI-eGFP was episomally maintained and conferred sustained eGFP expression even in nonselective conditions in the human cell line, K562, as well as in primary human fibroblast-like cells. In contrast, in the murine erythroleukemia cell line, MEL, transgene expression was silenced through histone deacetylation, despite the vector's episomal persistence. Hematopoietic semisolid cell colonies derived from transfected human cord blood CD34(+) cells expressed eGFP, albeit at low levels. After 4 weeks, the vector is retained in approximately 1% of progeny cells. Our results provide the first evidence that S/MAR-based plasmids can function as stable episomes in primary human cells, supporting long-term transgene expression. However, they do not display universal behavior in all cell types.

Animals↗
PubMed2005

Genetic modification of hematopoietic stem cells with nonviral systems: past progress and future prospects.

Serious unwanted complications provoked by retroviral gene transfer into hematopoietic stem cells (HSCs) have recently raised the need for the development and assessment of alternative gene transfer vectors. Within this context, nonviral gene transfer systems are attracting increasing interest. Their main advantages include low cost, ease of handling and large-scale production, large packaging capacity and, most importantly, biosafety. While nonviral gene transfer into HSCs has been restricted in the past by poor transfection efficiency and transient maintenance, in recent years, biotechnological developments are converting nonviral transfer into a realistic approach for genetic modification of cells of hematopoietic origin. Herein we provide an overview of past accomplishments in the field of nonviral gene transfer into hematopoietic progenitor/stem cells and we point at future challenges. We argue that episomally maintained self-replicating vectors combined with physical methods of delivery show the greatest promise among nonviral gene transfer strategies for the treatment of disorders of the hematopoietic system.

Animals↗
PubMed2002

Right ventricular cardiomyopathy in beta-thalassaemia major.

AIMS: To evaluate right ventricular function in patients with beta-thalassaemia major and congestive heart failure. Background In patients with beta-thalassaemia major a high incidence of cardiac involvement still exists despite improved prognosis with chelation therapy. Development of severe right heart failure is common and has been attributed to pulmonary hypertension secondary to lung haemochromatosis. However, the possibility of direct right ventricular myocardial involvement in the absence of significant pulmonary hypertension has not been adequately investigated. METHODS: Twenty-nine consecutively screened patients with beta-thalassaemia major and congestive heart failure were investigated by Doppler echocardiography, right ventricular first-pass radionuclide examination and cardiac catheterization. Haemodynamic data were obtained both before and after volume loading. A control group of 39 patients with beta-thalassaemia major, free from cardiac disease, and matched for age, gender, body surface area and heart rate was used for comparison. A subset of the control thalassaemic group (n=15) underwent both radionuclide and haemodynamic assessment. RESULTS: The majority of patients were on non-optimal chelation therapy. Only two of 29 patients were found to have cor pulmonale. One other patient suffered from constrictive pericarditis. A restrictive filling pattern in both ventricles and left ventricular systolic dysfunction were evident in the other 26 patients. Pulmonary artery pressure (systolic, 33+/-8 vs 27+/-5 mmHg, P<0.05) and pulmonary vascular resistance (114+/-56 vs 65+/-29 dynes. s. cm(-5), P<0.01) were only mildly elevated in the heart failure group. After volume challenge, cardiac output remained unchanged although the increments of ventricular filling pressures were significant (Deltaright atrial: 4.8+/-2.2 mmHg, P<0.05; Deltapulmonary capillary wedge: 5.6+/-2.9 mmHg, P<0.05) and correlated with each other (r=0.69;P<0.001) in heart failure patients, suggesting pericardial constraint and ventricular interaction. In these patients compared with the control thalassaemic group, a lower right ventricular ejection fraction (29%+/-9 vs 59%+/-6, P<0.0001) without correlation with pulmonary artery pressures was found. Haemodynamically significant right ventricular dysfunction defined as mean right atrial pressure >10 mmHg and ratio of mean right atrial-to-capillary wedge pressure >0.8 was evident in 15 of the 26 patients (58%), all with severe symptoms, representing three fourths of the patients in functional class III and IV. Simultaneous pressure recordings in six of these 15 patients showed equalization of ventricular end-diastolic pressures within 5 mmHg. CONCLUSION: The majority of patients with beta-thalassaemia major and severe congestive heart failure demonstrated a unique haemodynamic pattern similar to that described in predominant right ventricular infarction, indicating severe right ventricular cardiomyopathy in addition to left ventricular dysfunction. The incidence of cor pulmonale as a cause of right heart failure seems to be much lower than previously hypothesized.

Adult↗
PubMed2001

Right ventricular diastolic function in beta-thalassemia major: echocardiographic and clinical correlates.

BACKGROUND: Cardiac hemochromatosis remains the most frequent cause of death in beta-thalassemia major. Previous studies suggest an important right ventricular (RV) contribution to cardiac morbidity and mortality. Studies with Doppler echocardiography have shown contradictory results regarding left ventricular (LV) filling, whereas the RV filling characteristics have not been studied yet. We prospectively studied the pattern of RV filling and investigated echocardiographic and clinical correlates during baseline and follow-up examinations in patients with beta-thalassemia major. METHODS AND RESULTS: The study included 79 patients, aged 24.2 +/- 8.0 years, with homozygous beta-thalassemia major without symptoms of heart failure with normal LV function and 51 healthy control subjects, matched for age, sex, and body surface area. Doppler echocardiographic indexes of systolic and diastolic ventricular function were assessed. Hemodynamic measurements were obtained in 8 patients by right heart catheterization. An abnormal RV relaxation pattern was evident in the patient group. The LV filling characteristics indicated increased preload without abnormal alteration, whereas catheterization findings were consistent with a high cardiac output state. Short tricuspid deceleration time (DT) had the best predictive value for subsequent cardiac events. Repeat echocardiographic study in 35 asymptomatic patients at 19 +/- 7 months demonstrated deterioration of LV systolic function, chamber enlargement, and shortening of DT of tricuspid and mitral inflow. CONCLUSIONS: In patients with homozygous beta-thalassemia major without cardiac disease, the pattern of RV filling is abnormally altered, indicating impaired relaxation. In contrast, the LV filling is compatible with increased preload, as in chronic anemia. Short DT of early tricuspid inflow carries important prognostic value. LV remodeling occurs over time along with transition toward a restrictive ventricular filling pattern.

Adolescent↗
PubMed1999

Apoptosis in patients with myelodysplastic syndromes: differential involvement of marrow cells in 'good' versus 'poor' prognosis patients and correlation with apoptosis-related genes.

Apoptosis has been implicated in the pathogenesis of marrow failure in MDS and the coexistence of marrow hypercellularity along with blood cytopenias was seen as evidence of extreme cell death of mainly mature cells in the marrow (ineffective hematopoiesis). We investigated apoptosis in 53 patients with MDS, by using single-step DNA extraction and gel electrophoresis and then by separating fresh marrow mononuclear cells in CD34+ and CD34- populations and in situ single cell evaluation of the process. We also studied the expression of apoptosis-related genes, in total and separated mononuclear marrow cells and correlated the findings with clinical and laboratory characteristics. Patients with apoptosis had increased marrow cellularity, longer overall survival and a longer period for transformation to AML. In 'good' prognosis MDS patients, total mononuclear marrow cells, as well as isolated populations of CD34+ and CD34- cells showed significant degrees of apoptosis; in 'poor' prognosis cases, however, apoptosis was evident only in a large percentage of CD34+ marrow cells and not in total or CD34- cells. Absence of expression of both c-myc and p53 in total marrow cells was associated with significant degrees of apoptosis and in isolated CD34+ and CD34- marrow cells the phenomenon was inversely correlated with the level of bcl-2 expression. In conclusion, marrow apoptosis is detected in both CD34+ and CD34- cells in early MDS and seems to be restricted to CD34+ cells in advanced MDS cases.

Aged↗
PubMed1998

Dietary omega-3 polyunsaturated fatty acids plus vitamin E restore immunodeficiency and prolong survival for severely ill patients with generalized malignancy: a randomized control trial.

BACKGROUND: The aim of the current prospective, randomized control study was to investigate the effect of dietary omega-3 polyunsaturated fatty acids plus vitamin E on the immune status and survival of well-nourished and malnourished patients with generalized malignancy. METHODS: Sixty patients with generalized solid tumors were randomized to receive dietary supplementation with either fish oil (18 g of omega-3 polyunsaturated fatty acids, PUFA) or placebo daily until death. Each group included 15 well-nourished and 15 malnourished patients. The authors measured total T cells, T-helper cells, T-suppressor cells, natural killer cells, and the synthesis of interleukin-1, interleukin-6, and tumor necrosis factor by peripheral blood mononuclear cells before and on Day 40 of fish oil supplementation. Karnofsky performance status, nutritional state, and survival were also estimated. RESULTS: The ratio of T-helper cells to T-suppressor cells was significantly lower in malnourished patients. Omega-3 PUFA had a considerable immunomodulating effect by increasing this ratio in the subgroup of malnourished patients. There were no significant differences in cytokine production among the various groups, except for a decrease in tumor necrosis factor production in malnourished cancer patients, which was restored by omega-3 fatty acids. The mean survival was significantly higher for the subgroup of well-nourished patients in both groups, whereas omega-3 fatty acids prolonged the survival of all the patients. CONCLUSIONS: Malnutrition appears to be an important predictor of survival for patients with end stage malignant disease. Omega-3 polyunsaturated fatty acids had a significant immunomodulating effect and seemed to prolong the survival of malnourished patients with generalized malignancy.

Adjuvants, Immunologic↗
PubMed1997

A distinct pattern of cytokine production from blood mononuclear cells in multitransfused patients with beta-thalassaemia.

The unstimulated and induced production of granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), IL-3, IL-6, stem cell factor (SCF), IL-1beta, tumour necrosis factor-alpha (TNF-alpha), TNF-beta, interferon-gamma (IFN-gamma) and transforming growth factor-beta (TGF-beta) was determined after culture of blood mononuclear cells from 22 patients with severe beta-thalassaemia in a regular transfusion programme, five non-regularly transfused patients with beta-thalassaemia intermedia and nine normal persons. A distinct pattern of cytokine production in thalassaemic patients was detected, namely a low unstimulated production of all cytokines and a significant increase in the stimulated production of IFN-gamma, TNF-alpha and IL- 1beta; these abnormalities were more pronounced in the more heavily transfused older patients. The increased production of the above cytokines, which usually characterize the acute response to infectious agents and have a negative effect on erythropoiesis, may explain the deterioration of anaemia found in thalassaemic patients during acute infections.

Adolescent↗
PubMed1997

Sjögren's syndrome in patients with newly diagnosed untreated non-Hodgkin's lymphoma.

The purpose of the study was to detect cases of Sjögren's syndrome among newly diagnosed untreated patients with non-Hodgkin's lymphoma and, furthermore, to identify in such cases clinical and serologic features known to occur more frequently in Sjögren's syndrome patients who evolve into lymphoma. Accordingly, thirty-three cases of newly diagnosed non-Hodgkin's lymphoma, prior to any treatment administration, were thoroughly studied for evidence of Sjögren's syndrome. Immunophenotyping for T and B cells and kappa and lambda light chains was concomitantly performed on both lymphomatous tissues and minor salivary glands. There were 5 patients with T cell and 28 with B cell lymphoma of various histologic subtypes and grades. Two of the latter (7.1%) had a positive for Sjögren's syndrome minor labial salivary gland biopsy, positive responses to the specific questionnaires for both eye and mouth dryness and abnormal Schirmer's and rose Bengal eye tests, substantiating the diagnosis of Sjögren's syndrome. Both were male with lung and stomach non-Hodgkin's lymphoma respectively, enlargement of the lacrimal glands, monoclonal gammapathy of the IgM kappa type and, one of them had high titer and of fine speckled pattern positive antinuclear antibodies and anti-Ro(SSA) and anti-La(SSB) antibodies in his serum. A monotypic infiltrate with kappa light chain restriction, identical to that in the lymphomatous tissue of these two patients, was present in their minor salivary gland biopsy as well. Such a finding was not encountered in any of the remaining patients. Although our sample is relatively small, our results confirm the relationship between Sjögren's syndrome and non-Hodgkin's lymphoma, looked at from the opposite direction. Obviously, studies involving larger populations would be more definitive, regarding the issue of what percentage of this lymphoma patients originates from Sjögren's syndrome.

Adult↗
PubMed1995

The effect of parenteral indomethacin on T-lymphocyte subpopulations and cytokine production in patients under major surgical operations.

Major surgical trauma has been considered as a cause of immunosuppression mainly through the production of prostaglandin E2 from activated monocytes/macrophages. In the present study we investigated the effect of parenteral indomethacin--a cyclo-oxygenase inhibitor--on T-lymphocyte subsets and cytokine production in patients under major operations. We studied 20 patients undergoing major surgical procedures, 10 of whom were randomly treated pre- and post-operatively with indomethacin (group 2) and 10 were not (group 2). We measured total T-cells, T-helper, T-suppressor, T-helper/T-suppressor (Th/Ts) cell ratio, NK-cells and interleukin (IL-1) and tumor necrosis factor production by endotoxin- or phytohemagglutinin-stimulated peripheral blood mononuclear cells, before operation and at days 1, 3 and 7 postoperatively. We detected a significant increase in Th/Ts cell ratio and an improvement in delayed type hypersensitivity response in the treated group at day 3. We believe that the above immunomodulating effect of in vivo cyclo-oxygenase inhibition may be beneficial in patients under major surgical procedures with a high susceptibility to postoperative infections.

Adult↗
PubMed1995

The effect of dietary omega-3 polyunsaturated fatty acids on T-lymphocyte subsets of patients with solid tumors.

The effect of omega-3 polyunsaturated fatty acids (PUFA) on the immune system seems to be beneficial. There has been a number of studies concerning the effect of dietary omega-3 PUFA on different immune parameters. The aim of our present study was to investigate the effect of dietary omega-3 PUFA on T-cell subsets and natural killer (NK) cells of patients with solid tumors. We studied 20 patients with solid tumors who received 18 g fish oil/day for 40 consecutive days. We detected a significant increase in T-helper/T-suppressor cell ratio 40 days into omega-3 supplementation, due mainly to a decrease in the number of suppressor T cells. We concluded that dietary omega-3 fatty acids may have a beneficial effect on the already compromised immune system of patients suffering from solid tumors.

Adult↗
PubMed1994

Peripheral blood mononuclear cells from patients with rheumatoid arthritis suppress erythropoiesis in vitro via the production of tumor necrosis factor alpha.

Anemia is a frequent manifestation of rheumatoid arthritis, with a probably multifactorial etiology. We investigated the effect of peripheral blood mononuclear cell supernatants (PBMCS) from rheumatoid arthritis (RA) patients on hematopoietic colony formation in vitro, by using a methylcellulose assay. PBMCS from patients suppress in vitro erythroid (BFU-E), mixed-lineage (CFU-GEMM) and to a lesser degree granulocyte-macrophage (CFU-GM) progenitors. PBMCS from anemic RA patients were more suppressive for BFU-E than those from non-anemic patients. Addition of antibodies to tumor-necrosis factor alpha (TNF alpha) almost completely reversed the inhibition of BFU-E and CFU-GEMM, but had little effect on the CFU-GM colony formation. Antibodies to interferon-gamma (IFN gamma) and interleukin-1 (IL-1) were not effective. The above data suggest that PBMCS from RA patients suppress in vitro erythropoiesis via the production of TNF alpha; a pathogenetic role for TNF alpha in the anemia of RA can be implied.

Adult↗
PubMed1993

Biological strategies for the selective manipulation of normal and leukemic stem cells.

Recent developments have occurred in the identification and quantitation of a very primitive type of hematopoietic cell (referred to as a long-term culture initiating cell or LTC-IC) using defined long-term culture conditions. These have facilitated investigations of the numbers and properties of both normal and leukemic LTC-IC in patients with chronic myeloid leukemia (CML). Such studies have revealed that the marrow of many chronic phase patients contains a substantial population of normal LTC-IC that are functionally intact albeit suppressed in vivo. Leukemic LTC-IC are typically less numerous in the marrow of these patients but are found in elevated numbers in the peripheral blood which, on average, in total contains more leukemic LTC-IC than the marrow when the WBC count rises above 10(11) per liter. However, a very marked heterogeneity in all of these parameters exists among individual patients. Some of the properties of leukemic LTC-IC are indistinguishable from those of their normal counterparts. Others, particularly those typically associated with an activated state, are altered, although frequently in only 90% (or less) of the leukemic LTC-IC. A more marked disparity between primitive normal and leukemic LTC-IC is seen in terms of their relative abilities to maintain their numbers in vitro. At the level of primitive clonogenic cells, the leukemic population has been shown to exhibit an increased rate of turnover. This appears to be due to an inability of these cells to respond to the cytostatic effects of macrophage inflammatory protein-1 alpha (MIP-1 alpha). These findings provide new insights into the biology of CML and highlight the power of quantitative assays to guide the development of more generally applicable curative therapies.

Hematopoietic Stem Cell Transplantation↗
PubMed1992

Deformability of the erythrocyte membrane in patients with myelodysplastic syndromes.

One of the major determinants of erythrocyte survival is membrane deformability, and an important intrinsic parameter of membrane deformability is the shear elastic modulus (mu) with higher mu values corresponding to increased membrane rigidity. Using a micropipette technique, we determined the shear elastic modulus of erythrocytes from 21 patients with myelodysplastic syndromes (MDS). Ten thalassemic patients and 15 healthy subjects served as controls. The shear elastic modulus of MDS erythrocytes was very significantly increased in all the patients studied, reflecting the rigidity of the membrane; the value of mu was also significantly higher in comparison with thalassemic cells. These data point to a fundamental change in the mechanical properties of the erythrocyte membrane in MDS. Biochemical studies of the membrane composition are clearly needed.

Aged↗
PubMed1990

Effect of different types of total parenteral nutrition on T-lymphocyte subpopulations and NK cells.

Long-chain triglycerides (LCTs) contained in total parenteral nutrition (TPN) regimens provide a considerable energy substrate in malnourished patients. Their effect on the immune system is controversial, however. In this randomized, prospective study we investigated the possible differences between the effect of TPN with LCTs or medium-chain triglycerides (MCTs) on T-lymphocyte subpopulations. Our study included 15 normal subjects, 20 patients receiving glucose-based TPN, and 40 patients receiving glucose-fat-based TPN. In the last group 20 patients received TPN that included LCTs and 20 received 50% MCTs and 50% LCTs. T-lymphocyte subpopulations, including total T cells and T-helper, T-suppressor, and NK cells, as well as the ratio of helper to suppressor T cells were determined before and 10 d after initiation of TPN. We found a significant decrease in the ratio of helper to suppressor T cells in the LCT group although no such difference was detected in the MCT-LCT group. No difference whatever was found in total T cells and helper, suppressor, and NK cells.

Adult↗
PubMed1990

Different haematopoietic growth factors have different capacity in overcoming the in vitro interferon gamma-induced suppression of bone marrow progenitor cells.

Interferon gamma (IFN gamma) inhibits haematopoiesis in vitro and an in vivo role in bone marrow suppression has been implied from clinical studies. We investigated the capacity of three recombinant (r), human (h), haematopoietic growth factors to overcome the in vitro IFN gamma inhibition of bone marrow progenitor cells in a methylcellulose culture system. Granulocyte macrophage-colony stimulating factor (GM-CSF) partially reversed IFN gamma-induced suppression of granulocyte-macrophage colony formation, by increasing colony forming units-granulocyte macrophage (CFU-GM) in a proportion ranging from 54-101%. Interleukin-3 (IL-3) and granulocyte-colony stimulating factor (G-CSF) were much less effective. For erythropoiesis, IL-3 was much more effective and partially reversed IFN gamma-mediated inhibition by increasing burst forming units-erythroid (BFU-E) in a proportion ranging from 52-138%. GM-CSF and G-CSF had no significant effect on IFN gamma-induced suppression of BFU-E. In conclusion, haematopoietic growth factors have different capacity to overcome IFN gamma-induced suppression of marrow progenitor cells in vitro. The findings may have therapeutic implications, as combinations of growth factors may be more effective in treating bone marrow failure syndromes.

Bone Marrow Cells↗
PubMed1990

The in vitro effect of corticosteroids on T-lymphocyte subpopulations in patients with ulcerative colitis.

T-lymphocyte subpopulations were measured in the blood of 20 patients with ulcerative colitis (11 in clinical remission and 9 in exacerbation) and 9 healthy persons, before and after in vitro incubation with dexamethasone. Although we found no significant differences in the helper/suppressor T cell ratio between patients and controls before in vitro incubation, addition of dexamethasone in culture induced a significant decrease of the ratio only in patients with ulcerative colitis in exacerbation. The percentage of natural killer cells before and after incubation with dexamethasone was not altered.

Adolescent↗
PubMed1989

Chronic neutrophilic leukemia with dysplastic features. A new variant of the myelodysplastic syndromes.

We are reporting four patients who presented with a persistent increase of mature neutrophils and band forms, no monocytosis in repeated examinations and with dysplastic features in blood and bone marrow. Two of them developed acute myeloid leukemia (AML; FAB classification M1) and the other two were characterised by a progressively aggravating myelodysplasia. All the patients showed a poor response to treatment and died within a period of time ranging from 14 to 80 months after diagnosis. We are proposing the term chronic neutrophilic leukemia with dysplastic features (CNL-D) for this entity, and we believe that it represents a variant of the myelodysplastic syndromes.

Aged↗