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A Filippetti

Publications and source records attributed to A Filippetti.

10 recordsLinked to original sources
PubMed2005

Self-interaction errors in density-functional calculations of electronic transport.

All density-functional calculations of single-molecule transport to date have used continuous exchange-correlation approximations. The lack of derivative discontinuity in such calculations leads to the erroneous prediction of metallic transport for insulating molecules. A simple and computationally undemanding atomic self-interaction correction (SIC) opens conduction gaps in I-V characteristics that otherwise are predicted metallic, as in the case of the prototype Au/ditholated-benzene/Au junction.

Journal Article↗
PubMed2000

Magnetic stress as a driving force of structural distortions: the case of CrN

We show that the observed transition from rock salt to orthorhombic P(nma) symmetry in CrN can be understood in terms of stress anisotropy. Using local spin density functional theory, we find that the imbalance between stress stored in spin-paired and spin-unpaired Cr nearest neighbors causes the rock-salt structure to be unstable against distortions and justifies the observed antiferromagnetic ordering. This stress has a purely magnetic origin and may be important in any system where the coupling between spin ordering and structure is strong.

Journal Article↗
PubMed1988

Relapse after allogeneic bone marrow transplantation for Philadelphia chromosome positive chronic myeloid leukemia: cytogenetic analysis of 24 patients.

One hundred patients with chronic myeloid leukemia (CML) submitted to bone marrow transplantation (BMT) were included in a cooperative cytogenetic study. Relapse (defined on the basis of hematological and cytogenetic findings) occurred in 24 (24%) patients at different intervals after BMT. In 18 of these patients (studied on average 3.3 times between BMT and relapse) no Ph-positive metaphases were detected before relapse. Sixteen (75%) of the patients relapsed with the same chromosomal pattern as that seen before BMT; eight patients, of whom five relapsed in blast crisis, showed additional chromosomal abnormalities resembling those seen in non-transplanted patients. One of these patients relapsed in cells of donor origin. After recognition of relapse, various hematological and cytogenetic patterns were observed. Four patients showed spontaneous reversion to normal (donor-type) chromosomes and hematology. Two other patients were followed for prolonged periods with hypercellular marrows with more than 50% Ph-positive cells but with normal peripheral blood values. The majority of patients proceeded to clinical relapse and required treatment with chemotherapy. We conclude that the isolated finding of a minority of Ph-positive metaphases after BMT should not be classified as relapse; for patients who do relapse, the sequence of cytogenetic and hematological events thereafter is variable.

Adolescent↗
PubMed1987

Chromosome studies in patients with Philadelphia chromosome-positive chronic myeloid leukemia submitted to bone marrow transplantation--results of a European Cooperative Study.

The karyotypes of 74 patients with Ph-positive chronic myeloid leukemia submitted to bone marrow transplantation collected from nine institutions were studied serially before and after transplantation. In 13 cases sporadic Ph-positive metaphases were detected without signs of relapsing disease at various intervals after transplantation. These data indicate that the leukemic clone may not be completely suppressed by the conditioning treatment and that other biological mechanisms may be involved in destroying this clone or controlling its expansion.

Adolescent↗
PubMed1985

Fetal liver transplantation in the mini-pig.

After the characterisation of the hematological and immunological status of the mini-pig fetus at different gestational ages of development was performed, two different groups of animals receiving 800 rads of TBI given by a radioactive cobalt source at a dose/rate of 5/6 rad/min or 750 rads of TBI given by a Linear Accelerator at a dose/rate of 25/26 rad/min, both in a single dose exposure, were transplanted with a pool of allogeneic fetal liver cells whose age ranged between 55 and 75 days of gestation. In the first group 1 animal out of 6 is alive and well 30 months post-transplant. In the second group one of the nine transplanted animals survived 78 days. Engraftment was proved by the presence of the donor chromosome in the proliferating bone marrow cells in one animal.

Animals↗
PubMed1983

Fetal haemoglobin synthesis following fetal liver transplantation in man.

Transplantation of haematopoietic tissue from the fetus to the adult is of considerable clinical and theoretical interest. In particular it could help to understand whether the haemoglobin switch is under the influence of environmental factors or inherently programmed in the haemopoietic cell population. In the present study we have monitored haemoglobin synthesis following fetal liver transplantation (FLT) in a patient with acute leukaemia after intensive chemoradiotherapy. 28 days following FLT, the haemoglobin synthesis showed a predominantly fetal haemoglobin pattern, as determined by globin chain synthesis of bone marrow cells and by the peroxidase anti-peroxidase (PAP) method applied to bone marrow sections treated with anti-fetal haemoglobin antibodies. These findings demonstrate that, in man, fetal haemopoietic cells, transplanted into an adult environment, do not immediately switch to the production of adult haemoglobin.

Bone Marrow↗
PubMedDate not supplied

The onset of CML in blastic crisis: molecular features.

The lack of distinguishing characteristics between lymphoid blastic crisis (BC) of Philadelphia (Ph)+ chronic myeloid leukemia (CML) and Ph+ acute lymphoblastic leukemia (ALL) remains an exciting dilemma. Indeed, the genetic defect of approximately half of Ph+ ALL patients is identical to that identified in CML. Here we report the case of one patient admitted with immunological and molecular patterns indicative of Ph+ ALL. The patient was brought into complete remission by chemotherapy and was transplanted with an HLA identical sibling donor, but relapsed a few months later with immunological and molecular evidence of BC of CML, displaying myeloid markers and lacking lymphoid antigens and immunoglobulin heavy chain (IgH) rearrangement. This suggest a CML case with an initial BC without a previous chronic phase or supervening on a subclinical CML.

Adult↗