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Biomedical subjects

S Olivero

Publications and source records attributed to S Olivero.

At least 19 recordsLinked to original sources
PubMed2001

Detection of epithelial cells in hematopoietic organs of patients with breast cancer. Physiopathological significance and clinical consequences.

Breast cancer is the most frequent neoplastic disease in populations of developed countries. It will affect 1 of every 6 or 7 women during their lifetime. The disease eventually evolves to a metastatic stage, and currently appears to be not curable at that stage. Thus, understanding mechanisms that result in the establishment of tumor at sites distant from the primary location is of the utmost importance. Equally important is the definition of a metastatic state, especially in regard to the detection of micrometastases. Finally, the presence of circulating tumor cells in the peripheral blood of patients who undergo progenitor mobilization, collection and reinfusion may be of clinical significance in the setting of high-dose chemotherapy for breast cancer.

Bone Marrow↗
PubMed2000

Detection of different Ikaros isoforms in human leukaemias using real-time quantitative polymerase chain reaction.

The Ikaros gene is an essential regulator in development and haematopoiesis. Dysregulated Ikaros gene expression participates in leukaemic processes, as evidenced in animal models, and by analyses of blast-cell populations from leukaemic patients. We used real-time quantitative polymerase chain reaction (PCR) to evaluate the relative abundance of several Ikaros transcript isoforms in a variety of leukaemic-cell samples. Total RNA was isolated from bone-marrow or blood-cell samples collected at diagnosis in children or adult patients, 18 of whom had acute myeloblastic leukaemia (AML), 61 of whom had acute lymphoblastic leukaemia (ALL) and 11 of whom had chronic myeloid leukaemia (CML). The ratio (Ik1 + Ik2)/(Ik1 + Ik2 + Ik4 + Ik7 + Ik8) ranged from 13.5% to 85% and was lower (P < 0. 05) in samples from patients with m-bcr-abl ALL. An alternative splicing resulting in the deletion of 30 nucleotides at the end of exon 6 was observed in leukaemic samples, and in normal thymus and bone marrow. Our results are consistent with previous reports and suggest that the pattern of expression of the different human Ikaros isoforms are not homogeneous among different subsets of leukaemias.

Acute Disease↗
PubMed2000

Ex vivo expansion of human hematopoietic progenitors and cells to support high-dose chemoradiation therapy: five years of clinical experience.

The identification of cytokines-soluble or membrane-bound regulators of hematopoietic stem and progenitor cell survival, proliferation, and differentiation - and the definition of culture conditions that enable cell and progenitor expansion, has lead to the first clinical trials using cultured cells in addition to or in place of unmanipulated cells. The use of ex vivo expanded cells can improve several aspects of autologous and allogeneic hematopoietic cell and progenitor transplantation, such as reducing or abolishing the nadir that follows high-dose chemoradiation therapy regimens, or reducing the clinical risks associated with the use of small numbers of progenitors as in cord blood transplantation and in autologous transplantation for poor mobilizers. In addition, biological questions raised by ex vivo expansion are shared by scientists and clinicians interested in gene transfer into hematopoietic stem cells. We here review the biological problems associated with ex vivo expansion: defining efficient culture conditions, considering not only scientific and biological issues but also regulatory and commercial issues, defining appropriate surrogate endpoints that predict engraftment and superior clinical efficacy to that obtained with the use of unmanipulated grafts. We also review the results of the first clinical trials that have demonstrated the feasibilty of this approach, and have shown some of its limitations; demonstration of clinical efficacy will require more preclinical and clinical work.

Antineoplastic Agents↗
PubMed2000

CD34(+) immunoselected cells for poor graft function following allogeneic BMT.

BACKGROUND: Poor graft function without signs of graft rejection following allogeneic BMT (allo-BMT) occurs in around 9% of patients. A high incidence of hazardous complications may be encountered, leading to life-threatening situations. METHODS: We describe three patients who underwent allo-BMT for acute leukemia in first complete remission and untreated myelodysplastic syndrome. The three patients experienced prolonged and profound granulocytopenia, anemia and thrombocytopenia, despite growth factors and transfusions. This was not corrected by donor leukocytes infusion. They received a boost of CD34(+) positively-selected cells from their HLA-identical sibling donors. RESULTS: A rapid improvement of peripheral blood cell counts was observed in both patients who were in full donor chimerism status at time of boost infusion, whereas the patient with mixed chimerism did not show any signs of improvement. Neither patient suffered further exacerbation of GvHD. DISCUSSION: Allogeneic positively-immunoselected CD34(+) cells can represent an interesting alternative treatment for poor graft function following allo-BMT, in the absence of graft rejection signs.

Adult↗
PubMed1999

The role of autologous hematopoietic progenitor and cell reinfusion for intensive chemotherapy in women with poor-prognosis breast cancer. Clinical studies with ex-vivo expanded cells produced with the Aastrom Replicell technology.

In recent years, we have initiated two clinical studies, to evaluate the usefulness of ex-vivo expanded cells in patients with breast cancer who receive sequential high-dose chemotherapy. Ex-vivo expanded cells were produced from autologous cryopreserved bone marrow nucleated cells, using a biomedical device. The Aastrom Replicell system cultures cells in animal serum-replete medium, with a combination of flt3-L, PIXY321 and Epo, for 12 days. The initial pilot trial was set up to establish the feasibility and safety of the technique: 6 patients completed the study. An ongoing randomized study searches to establish whether ex-vivo expanded cells provide a clinical benefit.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

CD34+ cell enumeration in peripheral blood and apheresis samples, using two laboratory diagnostic kits or an institutional protocol.

In order to prepare the substitution of a commercially available diagnostic kit, ProCOUNT (Becton Dickinson) or Stem-Kit (Coulter Immunotech), for our institutional protocol, we compared the three techniques for the numeration of CD34+ progenitor cells in 50 peripheral blood and 51 apheresis samples, obtained from cancer patients or healthy donors. We show here that the three techniques yield results of the same order of magnitude. Although statistical analyses demonstrate significant differences between the three methods, these differences turned out to be clinically insignificant in most situations. Observed differences mostly affect samples with the highest content of CD34+ cells, while the three assays provide equivalent results for values that are close to clinically relevant thresholds (20 x 10(3) CD34+ cells/ml in peripheral blood to start apheresis, and accumulated number above 3 x 10(6) CD34+ cells/kg to stop apheresis). This study also supports the view that institutional protocols can provide a highly reliable determination of CD34+ cells counts and percentages. However, because institutional protocols often use research reagents and vary from institution to institution, the use of diagnostic kits may be prefered as one way to improve quality assurance in the practice of cell therapy.

Antigens, CD34↗
PubMed1997

Differential association of phosphatases with hematopoietic co-receptors bearing immunoreceptor tyrosine-based inhibition motifs.

A novel family of inhibitory co-receptors has been recently defined according to the presence in their intracytoplasmic domain of immunoreceptor tyrosine-based inhibition motifs (ITIM). In particular, this family includes a low-affinity receptor for IgG, Fc gammaRIIB, which is widely expressed on hematopoietic cells, as well as killer cell inhibitory receptors (KIR) for major histocompatibility complex (MHC) class I proteins, expressed on both T and natural killer (NK) lymphocytes. Fc gammaRIIB and KIR inhibitory function depends upon the tyrosine phosphorylation of their respective ITIM. Phosphorylated Fc gammaRIIB and KIR ITIM bind the tandem SH2 tyrosine phosphatases, SHP-1 and SHP-2. Recently, Fc gammaRIIB has been shown to associate with a polyphosphate inositol 5-phosphatase, SHIP, which appears to be involved in its inhibitory function. Using cell lysate adsorption to phosphorylated ITIM peptides and surface plasmon resonance, we demonstrate here that, in contrast to Fc gammaRIIB, KIR (CD158b: p58.2) do not bind to SHIP, and only recruit SHP-1 and SHP-2. In addition, we show that point mutation of the amino acid residue in position tyrosine-2 of Fc gammaRIIB and KIR ITIM abolihes their binding to SHP-1 and SHP-2, but leaves intact the association of SHIP with Fc gammaRIIB ITIM. These data contribute to the structural definition of ITIM and document a differential recruitment of phosphatases by distinct ITIM. These findings also reveal that diverse strategies of inhibition are used by distinct members of the ITIM-bearing co-receptor family.

Amino Acid Sequence↗
PubMed1997

Transduction of cytotoxic signals in natural killer cells: a general model of fine tuning between activatory and inhibitory pathways in lymphocytes.

NK-cells are large granular lymphocytes, which are capable of exerting two major types of effector function, cell cytotoxicity and lymphokine secretion. NK-cells can exert cell cytotoxicity in one of two ways. First, NK-cells are able to recognize and to induce the lysis of antibody-coated target cells during antibody-dependent cell cytotoxicity (ADCC). Second, during natural cytotoxicity NK-cells are also able to recognize and to induce the lysis of a variety of target cells, including primarily virus-infected cells as well as tumor cells. Recently, a novel mechanism has been elucidated which controls NK-cell-activation programs and which is based on the cell surface expression of killer-cell inhibitory receptors (KIR). We will review here the molecular dissection of this inhibitory signalling pathway which utilizes immunoreceptor tyrosine-based inhibition motifs (ITIM) expressed in KIR intracytoplasmic domain. We will also show that this strategy used by NK-cells to regulate their effector functions is a general decision mechanism which exists not only in T- and B-lymphocytes, but also in a variety of other hematopoietic cells.

Amino Acid Sequence↗
PubMed1991

Imipenem-cilastatin in the treatment of hospital infections.

Imipenem was tested on 65 gram-negative bacterial strains consecutively isolated in patients affected by hospital infection and used as empiric therapy in 52 patients presenting a hospital infection suspected of gram-negative origin. More than 96% of the tested strains resulted sensitive to imipenem. This antibiotic showed a good clinical result in more than 80% of the cases when used as therapy. Therefore imipenem could be considered the drug of first choice in patients with a severe prognosis and a nosocomial infection suspected to be due to a gram-negative microorganism.

Cilastatin↗
PubMed1987

[Hospital infections in an emergency surgery ward].

A study was conducted on hospital infections in an emergency surgery ward. The survey lasted one year and confirmed the higher incidence of infections after contaminated and dirty operations. Rates of infection were also high after clean operations due to the large number of subjects at risk among the group examined. The most commonly encountered micro-organisms in the infections of surgical wounds were, in order, E. coli, Str. faecalis and Staph. aureus, the latter being only minimally responsive to the standard antibiotics. Several proposals are advanced for prophylaxis in the attempt to halt the circulation of strains with a multiple resistance to antibiotics.

Age Factors↗